Materials Data on Ba2CdAs2 by Materials Project
Ba2CdAs2 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to five As3- atoms to form BaAs5 trigonal bipyramids that share corners with four equivalent CdAs4 tetrahedra, corners with eleven BaAs5 trigonal bipyramids, edges with three equivalent CdAs4 tetrahedra, and edges with four BaAs5 trigonal bipyramids. There are a spread of Ba–As bond distances ranging from 3.25–3.46 Å. In the second Ba2+ site, Ba2+ is bonded to five As3- atoms to form distorted BaAs5 trigonal bipyramids that share corners with two equivalent CdAs4 tetrahedra, corners with eleven BaAs5 trigonal bipyramids, edges with four equivalent CdAs4 tetrahedra, and edges with six BaAs5 trigonal bipyramids. There are a spread of Ba–As bond distances ranging from 3.23–3.41 Å. Cd2+ is bonded to four As3- atoms to form CdAs4 tetrahedra that share corners with four equivalent CdAs4 tetrahedra, corners with six BaAs5 trigonal bipyramids, and edges with seven BaAs5 trigonal bipyramids. There are a spread of Cd–As bond distances ranging from 2.78–3.00 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 8-coordinate geometry to six Ba2+ and two equivalent Cd2+ atoms. In the second As3- site, As3- is bonded to four Ba2+ and two equivalent Cd2+ atoms to form a mixture of distorted edge and corner-sharing AsBa4Cd2 octahedra. The corner-sharing octahedral tilt angles are 68°.