DOE OSTI2020
ScAg4 crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. Sc is bonded to twelve Ag atoms to form ScAg12 cuboctahedra that share corners with twelve AgSc3Ag9 cuboctahedra, edges with eight equivalent ScAg12 cuboctahedra, edges with sixteen AgSc3Ag9 cuboctahedra, faces with two equivalent ScAg12 cuboctahedra, and faces with sixteen AgSc3Ag9 cuboctahedra. There are eight shorter (2.95 Å) and four longer (2.99 Å) Sc–Ag bond lengths. There are two inequivalent Ag sites. In the first Ag site, Ag is bonded to three equivalent Sc and nine Ag atoms to form distorted AgSc3Ag9 cuboctahedra that share corners with three equivalent ScAg12 cuboctahedra, corners with nine equivalent AgSc3Ag9 cuboctahedra, edges with four equivalent ScAg12 cuboctahedra, edges with twenty AgSc3Ag9 cuboctahedra, faces with four equivalent ScAg12 cuboctahedra, and faces with fourteen AgSc3Ag9 cuboctahedra. There are a spread of Ag–Ag bond distances ranging from 2.95–2.99 Å. In the second Ag site, Ag is bonded to three equivalent Sc and nine Ag atoms to form distorted AgSc3Ag9 cuboctahedra that share corners with three equivalent ScAg12 cuboctahedra, corners with nine AgSc3Ag9 cuboctahedra, edges with four equivalent ScAg12 cuboctahedra, edges with twenty AgSc3Ag9 cuboctahedra, faces with four equivalent ScAg12 cuboctahedra, and faces with fourteen AgSc3Ag9 cuboctahedra. The Ag–Ag bond length is 2.99 Å.