Materials Data on CaMg6C by Materials Project

Abstract

CaMg6C crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ca is bonded to two equivalent Ca and ten Mg atoms to form a mixture of distorted edge, corner, and face-sharing CaCa2Mg10 cuboctahedra. Both Ca–Ca bond lengths are 3.52 Å. There are a spread of Ca–Mg bond distances ranging from 3.30–3.83 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a single-bond geometry to two equivalent Mg and one C atom. Both Mg–Mg bond lengths are 3.10 Å. The Mg–C bond length is 2.29 Å. In the second Mg site, Mg is bonded in a water-like geometry to two equivalent Ca and two equivalent C atoms. Both Mg–C bond lengths are 2.27 Å. In the third Mg site, Mg is bonded in a 8-coordinate geometry to two equivalent Ca and six Mg atoms. Both Mg–Mg bond lengths are 3.00 Å. In the fourth Mg site, Mg is bonded in a 2-coordinate geometry to four equivalent Ca and four Mg atoms. Both Mg–Mg bond lengths are 3.52 Å. C is bonded in a 6-coordinate geometry to six Mg atoms.