Materials Data on HfMg6C by Materials Project

Mg6HfC crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a single-bond geometry to six Mg and one C atom. There are a spread of Mg–Mg bond distances ranging from 2.92–3.47 Å. The Mg–C bond length is 2.17 Å. In the second Mg site, Mg is bonded in a single-bond geometry to six Mg and one C atom. There are two shorter (3.06 Å) and four longer (3.30 Å) Mg–Mg bond lengths. The Mg–C bond length is 2.14 Å. In the third Mg site, Mg is bonded in a 11-coordinate geometry to nine Mg and two equivalent Hf atoms. There are a spread of Mg–Mg bond distances ranging from 3.07–3.33 Å. There are one shorter (3.16 Å) and one longer (3.33 Å) Mg–Hf bond lengths. In the fourth Mg site, Mg is bonded in a 10-coordinate geometry to ten Mg atoms. Hf is bonded in a linear geometry to four equivalent Mg and two equivalent C atoms. Both Hf–C bond lengths are 2.24 Å. C is bonded to three Mg and two equivalent Hf atoms to form corner-sharing CHf2Mg3 square pyramids.