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DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six NaO6 octahedra, edges with six NaO6 octahedra, and edges with six TbO6 octahedra. The corner-sharing octahedra tilt angles range from 9–10°. There are four shorter (2.50 Å) and two longer (2.53 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four TbO6 octahedra, edges with four TbO6 octahedra, and edges with eight NaO6 octahedra. The corner-sharing octahedra tilt angles range from 9–10°. There are a spread of Na–O bond distances ranging from 2.43–2.63 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four TbO6 octahedra, edges with four TbO6 octahedra, and edges with eight NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–9°. There are a spread of Na–O bond distances ranging from 2.39–2.60 Å. There are two inequivalent Tb4+ sites. In the first Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are two shorter (2.28 Å) and four longer (2.29 Å) Tb–O bond lengths. In the second Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are four shorter (2.28 Å) and two longer (2.29 Å) Tb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the second O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the third O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–10°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with five equivalent TbO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Na–O bond distances ranging from 2.36–2.68 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with five equivalent TbO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Na–O bond distances ranging from 2.46–2.53 Å. Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent TbO6 octahedra, and edges with ten NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Tb–O bond distances ranging from 2.27–2.32 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two equivalent Tb4+ atoms to form a mixture of distorted edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 4–13°. In the second O2- site, O2- is bonded to four Na1+ and two equivalent Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 2–7°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaTbO2 by Materials Project

NaTbO2 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Na1+ is bonded to six equivalent O2- atoms to form distorted NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four equivalent NaO6 octahedra, edges with four equivalent NaO6 octahedra, and edges with eight equivalent TbO6 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are four shorter (2.34 Å) and two longer (2.94 Å) Na–O bond lengths. Tb3+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent TbO6 octahedra, edges with four equivalent TbO6 octahedra, and edges with eight equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are two shorter (2.31 Å) and four longer (2.34 Å) Tb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Na1+ and three equivalent Tb3+ atoms to form a mixture of distorted edge and corner-sharing ONa3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are two shorter (2.34 Å) and one longer (2.94 Å) O–Na bond lengths. In the second O2- site, O2- is bonded to three equivalent Na1+ and three equivalent Tb3+ atoms to form a mixture of distorted edge and corner-sharing ONa3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. In the third O2- site, O2- is bonded to three equivalent Na1+ and three equivalent Tb3+ atoms to form a mixture of distorted edge and corner-sharing ONa3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are two shorter (2.34 Å) and one longer (2.94 Å) O–Na bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are seventeen inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–3.06 Å. In the second Na1+ site, Na1+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Na–O bond distances ranging from 2.23–2.47 Å. In the third Na1+ site, Na1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.98 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.32–2.59 Å. In the fifth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.65 Å. In the sixth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.33–2.87 Å. In the seventh Na1+ site, Na1+ is bonded to six O2- atoms to form edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.38–2.47 Å. In the eighth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.93 Å. In the ninth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.26–2.72 Å. In the tenth Na1+ site, Na1+ is bonded in a 4-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.28–2.93 Å. In the eleventh Na1+ site, Na1+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.57 Å. In the twelfth Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.31–2.52 Å. In the thirteenth Na1+ site, Na1+ is bonded in a 3-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–2.89 Å. In the fourteenth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.76 Å. In the fifteenth Na1+ site, Na1+ is bonded in a 2-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.24–2.82 Å. In the sixteenth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.21–2.67 Å. In the seventeenth Na1+ site, Na1+ is bonded to six O2- atoms to form distorted edge-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.31–2.58 Å. There are eight inequivalent Tb4+ sites. In the first Tb4+ site, Tb4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Tb–O bond distances ranging from 2.23–2.45 Å. In the second Tb4+ site, Tb4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.21–2.81 Å. In the third Tb4+ site, Tb4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Tb–O bond distances ranging from 2.29–2.79 Å. In the fourth Tb4+ site, Tb4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.28–2.57 Å. In the fifth Tb4+ site, Tb4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.32–2.52 Å. In the sixth Tb4+ site, Tb4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.23–2.72 Å. In the seventh Tb4+ site, Tb4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.22–2.46 Å. In the eighth Tb4+ site, Tb4+ is bonded in a 6-coordinate geometry to seven O2- atoms. There are a spread of Tb–O bond distances ranging from 2.28–2.62 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded to six Na1+ and one Tb4+ atom to form distorted ONa6Tb pentagonal bipyramids that share corners with two ONa3Tb3 octahedra, a cornercorner with one ONa6Tb pentagonal bipyramid, and edges with three ONa3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 40–58°. In the second O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Tb4+ atom. In the third O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Tb4+ atom. In the fourth O2- site, O2- is bonded in a 7-coordinate geometry to four Na1+ and three Tb4+ atoms. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Tb4+ atom. In the sixth O2- site, O2- is bonded in a 7-coordinate geometry to six Na1+ and one Tb4+ atom. In the seventh O2- site, O2- is bonded in a 8-coordinate geometry to five Na1+, two Tb4+, and one O2- atom. The O–O bond length is 1.54 Å. In the eighth O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form distorted ONa3Tb3 octahedra that share edges with three ONa3Tb3 octahedra and an edgeedge with one ONa6Tb pentagonal bipyramid. In the ninth O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form distorted ONa3Tb3 octahedra that share a cornercorner with one ONa3Tb3 octahedra, a cornercorner with one ONa6Tb pentagonal bipyramid, edges with two ONa3Tb3 octahedra, and edges with two equivalent ONa6Tb pentagonal bipyramids. The corner-sharing octahedral tilt angles are 0°. In the tenth O2- site, O2- is bonded in a 6-coordinate geometry to four Na1+ and three Tb4+ atoms. In the eleventh O2- site, O2- is bonded in a 7-coordinate geometry to three Na1+, three Tb4+, and one O2- atom. The O–O bond length is 1.53 Å. In the twelfth O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form distorted ONa3Tb3 octahedra that share a cornercorner with one ONa6Tb pentagonal bipyramid, edges with three ONa3Tb3 octahedra, and an edgeedge with one ONa6Tb pentagonal bipyramid. In the thirteenth O2- site, O2- is bonded in a 6-coordinate geometry to three Na1+, two Tb4+, and one O2- atom. In the fourteenth O2- site, O2- is bonded to six Na1+ and one Tb4+ atom to form distorted ONa6Tb pentagonal bipyramids that share corners with two ONa3Tb3 octahedra, corners with two ONa6Tb pentagonal bipyramids, and edges with three ONa3Tb3 octahedra. The corner-sharing octahedra tilt angles range from 13–49°. In the fifteenth O2- site, O2- is bonded in a 5-coordinate geometry to four Na1+ and three Tb4+ atoms. In the sixteenth O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form distorted ONa3Tb3 octahedra that share a cornercorner with one ONa3Tb3 octahedra, a cornercorner with one ONa6Tb pentagonal bipyramid, edges with two ONa3Tb3 octahedra, and an edgeedge with one ONa6Tb pentagonal bipyramid. The corner-sharing octahedral tilt angles are 15°. In the seventeenth O2- site, O2- is bonded in a 7-coordinate geometry to four Na1+ and three Tb4+ atoms. In the eighteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Na1+, three Tb4+, and one O2- atom. In the nineteenth O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form distorted ONa3Tb3 octahedra that share a cornercorner with one ONa3Tb3 octahedra, a cornercorner with one ONa6Tb pentagonal bipyramid, edges with three ONa3Tb3 octahedra, and an edgeedge with one ONa6Tb pentagonal bipyramid. The corner-sharing octahedral tilt angles are 15°. In the twentieth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+ and three Tb4+ atoms. In the twenty-first O2- site, O2- is bonded to three Na1+ and three Tb4+ atoms to form a mixture of edge and corner-sharing ONa3Tb3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the twenty-second O2- site, O2- is bonded in a 6-coordinate geometry to three Na1+ and three Tb4+ atoms. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+ and three Tb4+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 6-coordinate geometry to five Na1+ and one Tb4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 is Caswellsilverite-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two TbO6 octahedra, corners with four NaO6 octahedra, edges with five TbO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Na–O bond distances ranging from 2.35–2.67 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with five TbO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are a spread of Na–O bond distances ranging from 2.36–2.57 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two TbO6 octahedra, corners with four NaO6 octahedra, edges with five TbO6 octahedra, and edges with seven NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are a spread of Na–O bond distances ranging from 2.42–2.52 Å. There are two inequivalent Tb4+ sites. In the first Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent TbO6 octahedra, and edges with ten NaO6 octahedra. The corner-sharing octahedra tilt angles range from 2–8°. There are a spread of Tb–O bond distances ranging from 2.26–2.34 Å. In the second Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with two TbO6 octahedra, corners with four NaO6 octahedra, edges with two TbO6 octahedra, and edges with ten NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. There are a spread of Tb–O bond distances ranging from 2.27–2.33 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. In the second O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the third O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–15°. In the fourth O2- site, O2- is bonded to four Na1+ and two equivalent Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 4–12°. In the fifth O2- site, O2- is bonded to four Na1+ and two equivalent Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 2–6°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 is Caswellsilverite-like structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four equivalent NaO6 octahedra, edges with five equivalent TbO6 octahedra, and edges with seven equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are a spread of Na–O bond distances ranging from 2.36–2.56 Å. Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four equivalent NaO6 octahedra, edges with two equivalent TbO6 octahedra, and edges with ten equivalent NaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are four shorter (2.30 Å) and two longer (2.34 Å) Tb–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Na1+ and two equivalent Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second O2- site, O2- is bonded to four equivalent Na1+ and two equivalent Tb4+ atoms to form a mixture of edge and corner-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–16°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na5TbO6 by Materials Project

Na5TbO6 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are four inequivalent Na sites. In the first Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are two shorter (2.44 Å) and four longer (2.45 Å) Na–O bond lengths. In the second Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 7–10°. All Na–O bond lengths are 2.45 Å. In the third Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent TbO6 octahedra, and edges with ten NaO6 octahedra. The corner-sharing octahedra tilt angles range from 1–8°. There are a spread of Na–O bond distances ranging from 2.41–2.60 Å. In the fourth Na site, Na is bonded to six O atoms to form NaO6 octahedra that share corners with two equivalent TbO6 octahedra, corners with four NaO6 octahedra, edges with two equivalent TbO6 octahedra, and edges with ten NaO6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Na–O bond distances ranging from 2.41–2.51 Å. Tb is bonded to six O atoms to form TbO6 octahedra that share corners with six NaO6 octahedra and edges with twelve NaO6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. All Tb–O bond lengths are 2.26 Å. There are three inequivalent O sites. In the first O site, O is bonded to five Na and one Tb atom to form a mixture of corner and edge-sharing ONa5Tb octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to five Na and one Tb atom to form a mixture of corner and edge-sharing ONa5Tb octahedra. The corner-sharing octahedra tilt angles range from 0–12°. In the third O site, O is bonded to five Na and one Tb atom to form a mixture of corner and edge-sharing ONa5Tb octahedra. The corner-sharing octahedra tilt angles range from 0–12°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2TbO3 by Materials Project

Na2TbO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four TbO6 octahedra, edges with four TbO6 octahedra, and edges with eight NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are a spread of Na–O bond distances ranging from 2.39–2.61 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with two equivalent NaO6 octahedra, corners with four TbO6 octahedra, edges with four TbO6 octahedra, and edges with eight NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are a spread of Na–O bond distances ranging from 2.43–2.66 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six NaO6 octahedra, edges with six NaO6 octahedra, and edges with six TbO6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are four shorter (2.50 Å) and two longer (2.53 Å) Na–O bond lengths. There are two inequivalent Tb4+ sites. In the first Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are two shorter (2.28 Å) and four longer (2.29 Å) Tb–O bond lengths. In the second Tb4+ site, Tb4+ is bonded to six O2- atoms to form TbO6 octahedra that share corners with six NaO6 octahedra, edges with three equivalent TbO6 octahedra, and edges with nine NaO6 octahedra. The corner-sharing octahedra tilt angles range from 8–10°. There are two shorter (2.28 Å) and four longer (2.29 Å) Tb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the second O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the third O2- site, O2- is bonded to four Na1+ and two Tb4+ atoms to form a mixture of corner and edge-sharing ONa4Tb2 octahedra. The corner-sharing octahedra tilt angles range from 0–10°.

36 MATERIALS SCIENCE↗