DOE OSTI2020
Ca(Au3Bi)2 is beta-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms. There are a spread of Ca–Au bond distances ranging from 3.34–3.38 Å. In the second Ca2+ site, Ca2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms. There are a spread of Ca–Au bond distances ranging from 3.32–3.37 Å. There are six inequivalent Au1- sites. In the first Au1- site, Au1- is bonded to one Ca2+, six Au1-, and five Bi2+ atoms to form a mixture of edge, corner, and face-sharing AuCaBi5Au6 cuboctahedra. There are a spread of Au–Au bond distances ranging from 2.84–2.89 Å. There are a spread of Au–Bi bond distances ranging from 3.29–3.38 Å. In the second Au1- site, Au1- is bonded to two equivalent Ca2+, six Au1-, and four Bi2+ atoms to form a mixture of edge, corner, and face-sharing AuCa2Bi4Au6 cuboctahedra. There are five shorter (2.85 Å) and one longer (2.87 Å) Au–Au bond lengths. There are a spread of Au–Bi bond distances ranging from 3.34–3.39 Å. In the third Au1- site, Au1- is bonded to three Ca2+, six Au1-, and three Bi2+ atoms to form a mixture of edge, corner, and face-sharing AuCa3Bi3Au6 cuboctahedra. There are a spread of Au–Au bond distances ranging from 2.84–2.89 Å. There are two shorter (3.37 Å) and one longer (3.42 Å) Au–Bi bond lengths. In the fourth Au1- site, Au1- is bonded to six Au1- and six Bi2+ atoms to form AuBi6Au6 cuboctahedra that share corners with eighteen AuCaBi5Au6 cuboctahedra, edges with six equivalent AuBi6Au6 cuboctahedra, and faces with eighteen AuCaBi5Au6 cuboctahedra. There are three shorter (3.33 Å) and three longer (3.34 Å) Au–Bi bond lengths. In the fifth Au1- site, Au1- is bonded to three equivalent Ca2+, six Au1-, and three equivalent Bi2+ atoms to form AuCa3Bi3Au6 cuboctahedra that share corners with eighteen AuCa3Bi3Au6 cuboctahedra, edges with six equivalent AuCa3Bi3Au6 cuboctahedra, and faces with eighteen AuCa2Bi4Au6 cuboctahedra. All Au–Bi bond lengths are 3.34 Å. In the sixth Au1- site, Au1- is bonded to three equivalent Ca2+, six Au1-, and three equivalent Bi2+ atoms to form AuCa3Bi3Au6 cuboctahedra that share corners with eighteen AuCa3Bi3Au6 cuboctahedra, edges with six equivalent AuCa3Bi3Au6 cuboctahedra, and faces with eighteen AuCaBi5Au6 cuboctahedra. All Au–Bi bond lengths are 3.36 Å. There are four inequivalent Bi2+ sites. In the first Bi2+ site, Bi2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms. In the second Bi2+ site, Bi2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms. In the third Bi2+ site, Bi2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms. In the fourth Bi2+ site, Bi2+ is bonded in a 12-coordinate geometry to twelve Au1- atoms.