Materials Data on Ca(Al2Cu)4 by Materials Project

Abstract

Ca(CuAl2)4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ca is bonded in a 12-coordinate geometry to eight equivalent Cu and twelve Al atoms. All Ca–Cu bond lengths are 3.39 Å. There are four shorter (3.09 Å) and eight longer (3.22 Å) Ca–Al bond lengths. Cu is bonded to two equivalent Ca, two equivalent Cu, and eight Al atoms to form a mixture of distorted edge, face, and corner-sharing CuCa2Al8Cu2 cuboctahedra. Both Cu–Cu bond lengths are 2.56 Å. There are four shorter (2.57 Å) and four longer (2.70 Å) Cu–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 10-coordinate geometry to one Ca, four equivalent Cu, and five Al atoms. There are a spread of Al–Al bond distances ranging from 2.68–2.82 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ca, four equivalent Cu, and six Al atoms. Both Al–Al bond lengths are 2.76 Å.