Materials Data on BaMg6Si by Materials Project
BaMg6Si crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba is bonded to ten Mg and two equivalent Si atoms to form a mixture of distorted corner and face-sharing BaMg10Si2 cuboctahedra. There are a spread of Ba–Mg bond distances ranging from 3.43–3.73 Å. Both Ba–Si bond lengths are 3.42 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a 1-coordinate geometry to two equivalent Ba, two equivalent Mg, and one Si atom. Both Mg–Mg bond lengths are 3.09 Å. The Mg–Si bond length is 2.78 Å. In the second Mg site, Mg is bonded in a 6-coordinate geometry to six Mg atoms. There are two shorter (3.25 Å) and four longer (3.33 Å) Mg–Mg bond lengths. In the third Mg site, Mg is bonded in a 2-coordinate geometry to two equivalent Ba, three Mg, and two equivalent Si atoms. The Mg–Mg bond length is 3.37 Å. Both Mg–Si bond lengths are 2.98 Å. In the fourth Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba and eight Mg atoms. Si is bonded in a 8-coordinate geometry to two equivalent Ba and six Mg atoms.