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DOE OSTI2020

Materials Data on Sr3(GeAs2)2 by Materials Project

Sr3(GeAs2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 3–10°. There are a spread of Sr–As bond distances ranging from 3.14–3.33 Å. In the second Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 2–10°. There are a spread of Sr–As bond distances ranging from 3.15–3.26 Å. In the third Sr2+ site, Sr2+ is bonded to six As3- atoms to form a mixture of corner and edge-sharing SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 2–7°. There are a spread of Sr–As bond distances ranging from 3.15–3.36 Å. There are two inequivalent Ge3+ sites. In the first Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are a spread of Ge–As bond distances ranging from 2.45–2.54 Å. In the second Ge3+ site, Ge3+ is bonded in a trigonal non-coplanar geometry to three As3- atoms. There are one shorter (2.50 Å) and two longer (2.52 Å) Ge–As bond lengths. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded to four Sr2+ and two equivalent Ge3+ atoms to form AsSr4Ge2 octahedra that share corners with eight AsSr5Ge octahedra and edges with eight AsSr4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 3–93°. In the second As3- site, As3- is bonded to four Sr2+ and two Ge3+ atoms to form a mixture of corner and edge-sharing AsSr4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 6–94°. In the third As3- site, As3- is bonded to five Sr2+ and one Ge3+ atom to form a mixture of corner and edge-sharing AsSr5Ge octahedra. The corner-sharing octahedra tilt angles range from 3–87°. In the fourth As3- site, As3- is bonded to five Sr2+ and one Ge3+ atom to form a mixture of corner and edge-sharing AsSr5Ge octahedra. The corner-sharing octahedra tilt angles range from 3–93°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Sr4GeAs4 by Materials Project

Sr4GeAs4 crystallizes in the cubic P-43n space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to six As3- atoms to form distorted SrAs6 octahedra that share corners with six SrAs6 octahedra, corners with three GeAs4 tetrahedra, edges with twelve SrAs6 octahedra, and a faceface with one GeAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 13–16°. There are a spread of Sr–As bond distances ranging from 3.17–3.37 Å. In the second Sr2+ site, Sr2+ is bonded to six As3- atoms to form SrAs6 octahedra that share corners with six equivalent SrAs6 octahedra, corners with three equivalent GeAs4 tetrahedra, edges with twelve SrAs6 octahedra, and a faceface with one GeAs4 tetrahedra. The corner-sharing octahedra tilt angles range from 14–15°. There are three shorter (3.21 Å) and three longer (3.37 Å) Sr–As bond lengths. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four equivalent As3- atoms to form GeAs4 tetrahedra that share corners with twelve SrAs6 octahedra and faces with four equivalent SrAs6 octahedra. The corner-sharing octahedra tilt angles range from 49–54°. All Ge–As bond lengths are 2.48 Å. In the second Ge4+ site, Ge4+ is bonded to four equivalent As3- atoms to form GeAs4 tetrahedra that share corners with twelve equivalent SrAs6 octahedra and faces with four equivalent SrAs6 octahedra. The corner-sharing octahedral tilt angles are 54°. All Ge–As bond lengths are 2.47 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded to six Sr2+ and one Ge4+ atom to form a mixture of distorted edge, corner, and face-sharing AsSr6Ge pentagonal bipyramids. In the second As3- site, As3- is bonded to six Sr2+ and one Ge4+ atom to form a mixture of distorted edge, corner, and face-sharing AsSr6Ge pentagonal bipyramids.

36 MATERIALS SCIENCE↗