Materials Data on Ca3(GeAs2)2 by Materials Project
Ca3(GeAs2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six As3- atoms to form a mixture of edge and corner-sharing CaAs6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Ca–As bond distances ranging from 3.01–3.19 Å. In the second Ca2+ site, Ca2+ is bonded to six As3- atoms to form a mixture of edge and corner-sharing CaAs6 octahedra. The corner-sharing octahedra tilt angles range from 1–7°. There are a spread of Ca–As bond distances ranging from 3.02–3.12 Å. In the third Ca2+ site, Ca2+ is bonded to six As3- atoms to form a mixture of edge and corner-sharing CaAs6 octahedra. The corner-sharing octahedra tilt angles range from 4–7°. There are a spread of Ca–As bond distances ranging from 2.99–3.11 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 2.48–2.50 Å. In the second 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 2.44–2.51 Å. There are four inequivalent As3- sites. In the first As3- site, As3- is bonded to five Ca2+ and one Ge3+ atom to form a mixture of edge and corner-sharing AsCa5Ge octahedra. The corner-sharing octahedra tilt angles range from 2–89°. In the second As3- site, As3- is bonded to four Ca2+ and two equivalent Ge3+ atoms to form a mixture of edge and corner-sharing AsCa4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 4–89°. In the third As3- site, As3- is bonded to four Ca2+ and two Ge3+ atoms to form a mixture of edge and corner-sharing AsCa4Ge2 octahedra. The corner-sharing octahedra tilt angles range from 4–91°. In the fourth As3- site, As3- is bonded to five Ca2+ and one Ge3+ atom to form AsCa5Ge octahedra that share corners with seven AsCa4Ge2 octahedra and edges with ten AsCa5Ge octahedra. The corner-sharing octahedra tilt angles range from 2–85°.