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DOE OSTI2020

Materials Data on RbHfMg30O31 by Materials Project

RbMg30HfO31 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded to five O atoms to form RbO5 square pyramids that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, corners with five MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are a spread of Rb–O bond distances ranging from 2.40–2.55 Å. There are sixteen inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent RbO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.93–2.26 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.13–2.21 Å. In the third Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one RbO5 square pyramid, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Mg–O bond distances ranging from 2.01–2.28 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.11–2.18 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.10–2.21 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.15–2.18 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, edges with eight MgO6 octahedra, an edgeedge with one RbO5 square pyramid, and edges with two MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Mg–O bond distances ranging from 2.10–2.28 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with nine MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Mg–O bond distances ranging from 2.16–2.21 Å. In the ninth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one RbO5 square pyramid, corners with four MgO5 square pyramids, an edgeedge with one HfO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Mg–O bond distances ranging from 2.06–2.28 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.14–2.19 Å. In the eleventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, an edgeedge with one RbO5 square pyramid, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 4–8°. There are a spread of Mg–O bond distances ranging from 2.07–2.26 Å. In the twelfth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.14–2.21 Å. In the thirteenth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one RbO5 square pyramid, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Mg–O bond distances ranging from 2.09–2.22 Å. In the fourteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–5°. There are a spread of Mg–O bond distances ranging from 2.10–2.24 Å. In the fifteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, an edgeedge with one RbO5 square pyramid, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Mg–O bond distances ranging from 2.11–2.21 Å. In the sixteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–5°. There are a spread of Mg–O bond distances ranging from 2.10–2.23 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent RbO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Hf–O bond distances ranging from 2.00–2.15 Å. There are seventeen inequivalent O sites. In the first O site, O is bonded to five Mg and one Hf atom to form a mixture of edge and corner-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the third O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the fourth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with four OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. In the fifth O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the sixth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the seventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. In the tenth O site, O is bonded to one Rb, four Mg, and one Hf atom to form ORbHfMg4 octahedra that share corners with six OMg6 octahedra and edges with eleven OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the twelfth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the thirteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fourteenth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with six OHfMg5 octahedra and edges with eleven OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the fifteenth O site, O is bonded to five Mg and one Hf atom to form a mixture of edge and corner-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the sixteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the seventeenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg14O15 by Materials Project

RbMg14HfO15 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded in a 5-coordinate geometry to five O atoms. There are two shorter (2.60 Å) and three longer (2.75 Å) Rb–O bond lengths. There are ten inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with eight MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 3°. There are a spread of Mg–O bond distances ranging from 2.00–2.18 Å. In the second Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Mg–O bond distances ranging from 2.01–2.09 Å. In the third Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share a cornercorner with one MgO6 octahedra, corners with four equivalent MgO5 square pyramids, and edges with four MgO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are a spread of Mg–O bond distances ranging from 1.98–2.24 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, a cornercorner with one MgO5 square pyramid, edges with six MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–9°. There are a spread of Mg–O bond distances ranging from 2.07–2.25 Å. In the fifth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share a cornercorner with one MgO6 octahedra, corners with two equivalent MgO5 square pyramids, and edges with four MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.03–2.09 Å. In the sixth Mg site, Mg is bonded in a distorted T-shaped geometry to three O atoms. There are two shorter (2.17 Å) and one longer (2.41 Å) Mg–O bond lengths. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, a cornercorner with one MgO5 square pyramid, edges with eight MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Mg–O bond distances ranging from 2.06–2.27 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, edges with six MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 4–12°. There are a spread of Mg–O bond distances ranging from 2.08–2.53 Å. In the ninth Mg site, Mg is bonded in a rectangular see-saw-like geometry to four O atoms. There are a spread of Mg–O bond distances ranging from 2.04–2.10 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, edges with seven MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Mg–O bond distances ranging from 2.07–2.32 Å. Hf is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.00 Å) and two longer (2.21 Å) Hf–O bond lengths. There are eleven inequivalent O sites. In the first O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with two equivalent ORbMg5 octahedra, a cornercorner with one OMg5 square pyramid, corners with four ORbHfMg3 trigonal bipyramids, edges with four OMg6 octahedra, and edges with four equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 6°. In the second O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share a cornercorner with one ORbMg5 octahedra, corners with four OMg5 square pyramids, corners with four ORb2Mg3 trigonal bipyramids, and edges with eight OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the third O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OMg5 square pyramids, corners with four OHf2Mg3 trigonal bipyramids, and edges with eight OMg6 octahedra. In the fourth O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share a cornercorner with one OMg6 octahedra, corners with four equivalent OMg5 square pyramids, and edges with six ORbMg5 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, a cornercorner with one OMg5 square pyramid, edges with four OMg6 octahedra, edges with four OMg5 square pyramids, and edges with four ORb2Mg3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 2–6°. In the sixth O site, O is bonded to two equivalent Rb and three Mg atoms to form ORb2Mg3 trigonal bipyramids that share corners with three ORbMg5 octahedra, corners with two equivalent OMg5 square pyramids, corners with four ORb2Mg3 trigonal bipyramids, edges with two equivalent OMg6 octahedra, and edges with four equivalent ORbHfMg3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–53°. In the seventh O site, O is bonded to three Mg and two equivalent Hf atoms to form OHf2Mg3 trigonal bipyramids that share a cornercorner with one OMg6 octahedra, corners with two equivalent OMg5 square pyramids, corners with four OHf2Mg3 trigonal bipyramids, edges with two equivalent OMg6 octahedra, and edges with four equivalent ORbHfMg3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one ORb2Mg3 trigonal bipyramid, edges with eight ORbMg5 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 3–4°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one OHf2Mg3 trigonal bipyramid, edges with six OMg6 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 4–16°. In the tenth O site, O is bonded to one Rb, three Mg, and one Hf atom to form distorted ORbHfMg3 trigonal bipyramids that share corners with two ORbMg5 octahedra, corners with two OMg5 square pyramids, corners with four equivalent ORbHfMg3 trigonal bipyramids, edges with two equivalent OMg6 octahedra, and edges with four OHf2Mg3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 9–60°. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, a cornercorner with one ORbHfMg3 trigonal bipyramid, edges with seven ORbMg5 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 3–10°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg6O7 by Materials Project

RbMg6HfO7 crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one RbMg6HfO7 sheet oriented in the (0, 0, 1) direction. Rb is bonded in a 4-coordinate geometry to four equivalent O atoms. All Rb–O bond lengths are 2.91 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form a mixture of distorted corner and edge-sharing MgO5 square pyramids. There are one shorter (1.97 Å) and four longer (2.11 Å) Mg–O bond lengths. In the second Mg site, Mg is bonded to five O atoms to form a mixture of distorted corner and edge-sharing MgO5 trigonal bipyramids. There are one shorter (2.05 Å) and four longer (2.12 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded in a single-bond geometry to one O atom. The Mg–O bond length is 2.04 Å. In the fourth Mg site, Mg is bonded to five O atoms to form a mixture of distorted corner and edge-sharing MgO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 1.99–2.13 Å. Hf is bonded in a 5-coordinate geometry to five O atoms. There are one shorter (1.89 Å) and four longer (2.11 Å) Hf–O bond lengths. There are five inequivalent O sites. In the first O site, O is bonded to five Mg atoms to form distorted corner-sharing OMg5 trigonal bipyramids. In the second O site, O is bonded to four equivalent Rb and one Hf atom to form a mixture of distorted corner and edge-sharing ORb4Hf square pyramids. In the third O site, O is bonded in a 5-coordinate geometry to five Mg atoms. In the fourth O site, O is bonded in a 3-coordinate geometry to one Mg and two equivalent Hf atoms. In the fifth O site, O is bonded to five Mg atoms to form a mixture of distorted corner and edge-sharing OMg5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg6O7 by Materials Project

RbMg6HfO7 crystallizes in the tetragonal P4mm space group. The structure is two-dimensional and consists of one RbMg6HfO7 sheet oriented in the (0, 0, 1) direction. Rb is bonded in a 4-coordinate geometry to four equivalent O atoms. All Rb–O bond lengths are 2.70 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form a mixture of edge and corner-sharing MgO5 square pyramids. There are four shorter (2.12 Å) and one longer (2.43 Å) Mg–O bond lengths. In the second Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with five MgO5 square pyramids, corners with four equivalent MgO5 trigonal bipyramids, and edges with four equivalent HfO6 octahedra. There are one shorter (2.01 Å) and four longer (2.15 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded in a 2-coordinate geometry to three O atoms. There are two shorter (2.18 Å) and one longer (2.64 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to five O atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent HfO6 octahedra, corners with two equivalent MgO5 square pyramids, corners with four equivalent MgO5 trigonal bipyramids, edges with two equivalent MgO5 square pyramids, and edges with four equivalent MgO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 71°. There are a spread of Mg–O bond distances ranging from 1.92–2.24 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with four equivalent HfO6 octahedra, corners with four equivalent MgO5 trigonal bipyramids, and edges with four equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 2°. There are a spread of Hf–O bond distances ranging from 2.03–2.15 Å. There are five inequivalent O sites. In the first O site, O is bonded to four equivalent Mg and one Hf atom to form distorted corner-sharing OHfMg4 trigonal bipyramids. In the second O site, O is bonded in a 5-coordinate geometry to four equivalent Mg and one Hf atom. In the third O site, O is bonded in a 6-coordinate geometry to six Mg atoms. In the fourth O site, O is bonded to two equivalent Rb and three Mg atoms to form a mixture of distorted edge and corner-sharing ORb2Mg3 trigonal bipyramids. In the fifth O site, O is bonded in a 4-coordinate geometry to three Mg and two equivalent Hf atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg30O31 by Materials Project

RbMg30HfO31 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded to six O atoms to form RbO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are one shorter (2.42 Å) and five longer (2.43 Å) Rb–O bond lengths. There are sixteen inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with two equivalent RbO6 octahedra, corners with two equivalent HfO6 octahedra, corners with five MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 1.92–2.26 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.92–2.25 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.92–2.23 Å. In the fourth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, corners with five MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.13 Å) and two longer (2.21 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.12–2.20 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.14–2.23 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, an edgeedge with one HfO6 octahedra, edges with seven MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–16°. There are a spread of Mg–O bond distances ranging from 2.15–2.22 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with nine MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 2–4°. There are two shorter (2.16 Å) and four longer (2.19 Å) Mg–O bond lengths. In the ninth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, corners with five MgO5 square pyramids, an edgeedge with one RbO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–13°. There are a spread of Mg–O bond distances ranging from 2.15–2.23 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.11–2.24 Å. In the eleventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one RbO6 octahedra, edges with nine MgO6 octahedra, and edges with two MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Mg–O bond distances ranging from 2.13–2.23 Å. In the twelfth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.11–2.24 Å. In the thirteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one RbO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Mg–O bond distances ranging from 2.14–2.22 Å. In the fourteenth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, corners with five MgO5 square pyramids, an edgeedge with one HfO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–7°. There are a spread of Mg–O bond distances ranging from 2.13–2.25 Å. In the fifteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Mg–O bond distances ranging from 2.14–2.23 Å. In the sixteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, and edges with two MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Mg–O bond distances ranging from 2.11–2.23 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.09 Å) and two longer (2.13 Å) Hf–O bond lengths. There are seventeen inequivalent O sites. In the first O site, O is bonded to one Rb and five Mg atoms to form a mixture of edge and corner-sharing ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the third O site, O is bonded to five Mg and one Hf atom to form a mixture of edge and corner-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the fourth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 3–6°. In the sixth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the seventh O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the tenth O site, O is bonded to one Rb and five Mg atoms to form distorted ORbMg5 octahedra that share corners with six OHfMg5 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the eleventh O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the twelfth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the thirteenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the fourteenth O site, O is bonded to one Rb and five Mg atoms to form distorted ORbMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the fifteenth O site, O is bonded to five Mg and one Hf atom to form a mixture of edge and corner-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the sixteenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the seventeenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg30O31 by Materials Project

RbMg30HfO31 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded to six O atoms to form RbO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent HfO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Rb–O bond distances ranging from 2.39–2.43 Å. There are sixteen inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 1.91–2.23 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent HfO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.11–2.20 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.90–2.23 Å. In the fourth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one HfO5 square pyramid, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are a spread of Mg–O bond distances ranging from 2.11–2.19 Å. In the fifth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.10–2.19 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.13–2.17 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, edges with eight MgO6 octahedra, an edgeedge with one HfO5 square pyramid, and edges with two MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 2–13°. There are a spread of Mg–O bond distances ranging from 2.08–2.28 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with nine MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.15–2.19 Å. In the ninth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one HfO5 square pyramid, corners with four MgO5 square pyramids, an edgeedge with one RbO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–13°. There are a spread of Mg–O bond distances ranging from 2.06–2.36 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–4°. There are four shorter (2.15 Å) and two longer (2.19 Å) Mg–O bond lengths. In the eleventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one RbO6 octahedra, edges with nine MgO6 octahedra, an edgeedge with one MgO5 square pyramid, and an edgeedge with one HfO5 square pyramid. The corner-sharing octahedra tilt angles range from 2–9°. There are one shorter (2.10 Å) and five longer (2.17 Å) Mg–O bond lengths. In the twelfth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.14–2.18 Å. In the thirteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one RbO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.11–2.24 Å. In the fourteenth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one HfO5 square pyramid, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.10–2.25 Å. In the fifteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are a spread of Mg–O bond distances ranging from 2.12–2.21 Å. In the sixteenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, an edgeedge with one MgO5 square pyramid, and an edgeedge with one HfO5 square pyramid. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.14–2.18 Å. Hf is bonded to five O atoms to form distorted HfO5 square pyramids that share corners with two equivalent RbO6 octahedra, corners with two equivalent MgO6 octahedra, corners with five MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 7–10°. There are a spread of Hf–O bond distances ranging from 1.97–2.37 Å. There are seventeen inequivalent O sites. In the first O site, O is bonded to one Rb and five Mg atoms to form a mixture of edge and corner-sharing ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the third O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the fourth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the fifth O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with four ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the sixth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the seventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. In the tenth O site, O is bonded to one Rb, four Mg, and one Hf atom to form ORbHfMg4 octahedra that share corners with six OMg6 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 4–15°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the twelfth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with eleven ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the thirteenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the fourteenth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the fifteenth O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with eleven OMg6 octahedra. The corner-sharing octahedra tilt angles range from 1–12°. In the sixteenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the seventeenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OHfMg5 octahedra and edges with eleven OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg14O15 by Materials Project

RbMg14HfO15 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.60 Å) and two longer (2.73 Å) Rb–O bond lengths. There are ten inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO5 square pyramids and edges with eight MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 1.99–2.17 Å. In the second Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO5 square pyramids and edges with eight MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.10 Å. In the third Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share a cornercorner with one MgO6 octahedra, corners with four equivalent MgO5 square pyramids, edges with four MgO6 octahedra, and edges with two equivalent HfO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 4°. There are a spread of Mg–O bond distances ranging from 1.97–2.29 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, a cornercorner with one MgO5 square pyramid, edges with four MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.06–2.29 Å. In the fifth Mg site, Mg is bonded in a T-shaped geometry to three O atoms. There are one shorter (2.06 Å) and two longer (2.18 Å) Mg–O bond lengths. In the sixth Mg site, Mg is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Mg–O bond distances ranging from 2.08–2.67 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, edges with six MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Mg–O bond distances ranging from 2.04–2.30 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent HfO5 trigonal bipyramids, edges with six MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.07–2.55 Å. In the ninth Mg site, Mg is bonded in a see-saw-like geometry to four O atoms. There are a spread of Mg–O bond distances ranging from 2.09–2.39 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, a cornercorner with one HfO5 trigonal bipyramid, edges with six MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 4–14°. There are a spread of Mg–O bond distances ranging from 2.09–2.37 Å. Hf is bonded to five O atoms to form distorted HfO5 trigonal bipyramids that share corners with four MgO6 octahedra, corners with two equivalent HfO5 trigonal bipyramids, and edges with four equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 59–77°. There are a spread of Hf–O bond distances ranging from 2.01–2.14 Å. There are eleven inequivalent O sites. In the first O site, O is bonded in a 5-coordinate geometry to four Mg and one Hf atom. In the second O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OMg5 square pyramids, corners with two equivalent ORb2Mg3 trigonal bipyramids, and edges with eight OMg6 octahedra. In the third O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OMg5 square pyramids, corners with two equivalent OHf2Mg3 trigonal bipyramids, and edges with eight OMg6 octahedra. In the fourth O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share a cornercorner with one OMg6 octahedra, corners with four equivalent OMg5 square pyramids, and edges with four OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, a cornercorner with one OMg5 square pyramid, edges with four OMg6 octahedra, edges with four OMg5 square pyramids, and edges with two ORb2Mg3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 1–4°. In the sixth O site, O is bonded to two equivalent Rb and three Mg atoms to form ORb2Mg3 trigonal bipyramids that share a cornercorner with one OMg6 octahedra, corners with two equivalent OMg5 square pyramids, corners with four OHf2Mg3 trigonal bipyramids, and edges with two equivalent OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to three Mg and two equivalent Hf atoms to form distorted OHf2Mg3 trigonal bipyramids that share a cornercorner with one OMg6 octahedra, corners with two equivalent OMg5 square pyramids, corners with four ORb2Mg3 trigonal bipyramids, and edges with two equivalent OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one ORb2Mg3 trigonal bipyramid, edges with six OMg6 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 2–5°. In the ninth O site, O is bonded to six Mg atoms to form distorted OMg6 octahedra that share corners with four OMg6 octahedra, a cornercorner with one OHf2Mg3 trigonal bipyramid, edges with six OMg6 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 2–9°. In the tenth O site, O is bonded in a 5-coordinate geometry to one Rb, three Mg, and one Hf atom. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, edges with six OMg6 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 2–15°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbHfMg30O31 by Materials Project

RbMg30HfO31 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. Rb is bonded to five O atoms to form RbO5 square pyramids that share corners with four equivalent MgO6 octahedra, corners with five MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are four shorter (2.45 Å) and one longer (2.54 Å) Rb–O bond lengths. There are ten inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, corners with two equivalent RbO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.93–2.26 Å. In the second Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four equivalent MgO6 octahedra, a cornercorner with one RbO5 square pyramid, corners with four equivalent MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are one shorter (2.01 Å) and four longer (2.26 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.10–2.21 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are four shorter (2.16 Å) and two longer (2.18 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, edges with eight MgO6 octahedra, an edgeedge with one RbO5 square pyramid, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–16°. There are a spread of Mg–O bond distances ranging from 2.14–2.23 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with nine MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 2–5°. There are a spread of Mg–O bond distances ranging from 2.16–2.20 Å. In the seventh Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with four MgO6 octahedra, a cornercorner with one RbO5 square pyramid, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Mg–O bond distances ranging from 2.11–2.22 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.10–2.23 Å. In the ninth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, an edgeedge with one RbO5 square pyramid, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Mg–O bond distances ranging from 2.12–2.19 Å. In the tenth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Mg–O bond distances ranging from 2.10–2.25 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Hf–O bond distances ranging from 2.10–2.13 Å. There are eleven inequivalent O sites. In the first O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OMg6 octahedra and edges with twelve OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O site, O is bonded to one Rb and five Mg atoms to form a mixture of corner and edge-sharing ORbMg5 octahedra. The corner-sharing octahedral tilt angles are 5°. In the fourth O site, O is bonded to six Mg atoms to form a mixture of corner and edge-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fifth O site, O is bonded to five Mg and one Hf atom to form a mixture of corner and edge-sharing OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the sixth O site, O is bonded to six Mg atoms to form a mixture of corner and edge-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the eighth O site, O is bonded to one Rb and five Mg atoms to form ORbMg5 octahedra that share corners with six OHfMg5 octahedra and edges with eleven OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the ninth O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the tenth O site, O is bonded to six Mg atoms to form a mixture of corner and edge-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°.

36 MATERIALS SCIENCE↗