Materials Data on KMg14BO16 by Materials Project
KMg14BO16 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with two equivalent KO6 octahedra, corners with two equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of K–O bond distances ranging from 2.22–2.74 Å. There are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent KO6 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 2.02–2.22 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.04–2.22 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent KO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–31°. There are a spread of Mg–O bond distances ranging from 1.98–2.31 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.05–2.27 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent KO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Mg–O bond distances ranging from 2.05–2.24 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Mg–O bond distances ranging from 2.05–2.25 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent KO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Mg–O bond distances ranging from 2.05–2.24 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one KO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–31°. There are a spread of Mg–O bond distances ranging from 2.02–2.45 Å. B3+ is bonded in a distorted linear geometry to four O2- atoms. There is two shorter (1.37 Å) and two longer (2.22 Å) B–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form OKMg5 octahedra that share corners with four equivalent OKMg5 octahedra, corners with two equivalent OMg5 square pyramids, and edges with ten OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the second O2- site, O2- is bonded to five Mg2+ atoms to form distorted OMg5 square pyramids that share corners with four OKMg5 octahedra, corners with three equivalent OMg5 square pyramids, and edges with eight OMg6 octahedra. The corner-sharing octahedra tilt angles range from 2–85°. In the third O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with eight OKMg5 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 0–9°. In the fourth O2- site, O2- is bonded to two equivalent K1+ and four Mg2+ atoms to form OK2Mg4 octahedra that share corners with six OK2Mg4 octahedra and edges with eight OKMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded to four Mg2+ and two equivalent B3+ atoms to form OMg4B2 octahedra that share corners with six OK2Mg4 octahedra, corners with four equivalent OMg5 square pyramids, and edges with four equivalent OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OK2Mg4 octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg4B2 octahedra, edges with eight OMg6 octahedra, and edges with four equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, four Mg2+, and one B3+ atom. In the ninth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with four equivalent OMg6 octahedra, edges with ten OKMg5 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°.