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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Sr4Ta2O9 by Materials Project

Sr4Ta2O9 is Orthorhombic Perovskite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are five inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six TaO6 octahedra. The corner-sharing octahedra tilt angles range from 30–34°. There are a spread of Sr–O bond distances ranging from 2.41–2.45 Å. In the second Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six TaO6 octahedra. The corner-sharing octahedra tilt angles range from 31–36°. There are a spread of Sr–O bond distances ranging from 2.42–2.44 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.91 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.49–3.00 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.46–3.07 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three SrO6 octahedra and corners with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 22–36°. There are a spread of Ta–O bond distances ranging from 1.92–2.19 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three SrO6 octahedra and corners with three TaO6 octahedra. The corner-sharing octahedra tilt angles range from 25–34°. There are a spread of Ta–O bond distances ranging from 1.94–2.19 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded to two Sr2+ and two Ta5+ atoms to form distorted corner-sharing OSr2Ta2 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to four Sr2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Ta5+ atom. In the seventh O2- site, O2- is bonded to three Sr2+ and one Ta5+ atom to form distorted corner-sharing OSr3Ta tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 5-coordinate geometry to three Sr2+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr4Ta2O9 by Materials Project

Sr4Ta2O9 is Ilmenite-like structured and crystallizes in the trigonal P-3c1 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six equivalent O2- atoms to form distorted SrO6 octahedra that share corners with six equivalent TaO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, edges with three equivalent SrO6 octahedra, and a faceface with one SrO6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 39–57°. There are three shorter (2.50 Å) and three longer (2.70 Å) Sr–O bond lengths. In the second Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with three equivalent SrO6 octahedra, corners with three equivalent TaO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, edges with three equivalent TaO6 octahedra, and a faceface with one SrO6 octahedra. The corner-sharing octahedra tilt angles range from 48–62°. There are three shorter (2.41 Å) and three longer (2.55 Å) Sr–O bond lengths. Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with six equivalent SrO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, edges with three equivalent SrO6 pentagonal pyramids, and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 39–57°. There are three shorter (1.94 Å) and three longer (2.14 Å) Ta–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+ and two equivalent Ta5+ atoms to form a mixture of distorted corner and edge-sharing OSr2Ta2 trigonal pyramids. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr4Ta2O9 by Materials Project

Sr4Ta2O9 is Krennerite-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are five inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 3-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.54–3.24 Å. In the second Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six equivalent TaO6 octahedra and corners with six equivalent SrO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 33–34°. There are four shorter (2.53 Å) and two longer (2.54 Å) Sr–O bond lengths. In the third Sr2+ site, Sr2+ is bonded to six O2- atoms to form SrO6 octahedra that share corners with six equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–36°. All Sr–O bond lengths are 2.47 Å. In the fourth Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with three equivalent SrO6 octahedra, corners with three equivalent TaO6 octahedra, and edges with three equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 21–70°. There are a spread of Sr–O bond distances ranging from 2.49–2.65 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.44–2.70 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent SrO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 34–36°. There are a spread of Ta–O bond distances ranging from 1.90–2.19 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with three equivalent SrO6 octahedra, edges with three equivalent SrO6 pentagonal pyramids, and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 33–34°. There are a spread of Ta–O bond distances ranging from 1.92–2.17 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to three Sr2+ and two Ta5+ atoms to form a mixture of distorted edge and corner-sharing OSr3Ta2 trigonal bipyramids. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Sr2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Sr2+ and one Ta5+ atom. In the sixth O2- site, O2- is bonded to three Sr2+ and two Ta5+ atoms to form a mixture of distorted edge and corner-sharing OSr3Ta2 trigonal bipyramids. In the seventh O2- site, O2- is bonded to three Sr2+ and two Ta5+ atoms to form a mixture of distorted edge and corner-sharing OSr3Ta2 trigonal bipyramids. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Sr2+ and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr4Ta2O9 by Materials Project

Sr4Ta2O9 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 pentagonal pyramids that share corners with three equivalent SrO6 octahedra, corners with three equivalent TaO6 octahedra, a cornercorner with one SrO6 pentagonal pyramid, edges with three equivalent TaO6 octahedra, edges with two equivalent SrO6 pentagonal pyramids, and a faceface with one SrO6 octahedra. The corner-sharing octahedra tilt angles range from 49–57°. There are a spread of Sr–O bond distances ranging from 2.37–2.69 Å. In the second Sr2+ site, Sr2+ is bonded to six O2- atoms to form distorted SrO6 octahedra that share corners with six equivalent TaO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, edges with three equivalent SrO6 octahedra, and a faceface with one SrO6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 40–55°. There are a spread of Sr–O bond distances ranging from 2.45–2.80 Å. Ta5+ is bonded to six O2- atoms to form distorted TaO6 octahedra that share corners with six equivalent SrO6 octahedra, corners with three equivalent SrO6 pentagonal pyramids, edges with three equivalent SrO6 pentagonal pyramids, and a faceface with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 40–55°. There are a spread of Ta–O bond distances ranging from 1.91–2.18 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sr2+ and two equivalent Ta5+ atoms to form a mixture of distorted edge and corner-sharing OSr2Ta2 tetrahedra. In the second O2- site, O2- is bonded to two equivalent Sr2+ and two equivalent Ta5+ atoms to form a mixture of distorted edge and corner-sharing OSr2Ta2 trigonal pyramids. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Sr2+ and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Sr2+ and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four Sr2+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗