Materials Data on BaHfMg6 by Materials Project

Abstract

BaMg6Hf crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba is bonded to twelve Mg atoms to form BaMg12 cuboctahedra that share corners with four equivalent BaMg12 cuboctahedra, corners with eight equivalent HfMg12 cuboctahedra, edges with eight equivalent MgBa2Hf2Mg8 cuboctahedra, faces with two equivalent BaMg12 cuboctahedra, faces with four equivalent MgBa2Hf2Mg8 cuboctahedra, and faces with four equivalent HfMg12 cuboctahedra. There are a spread of Ba–Mg bond distances ranging from 3.35–3.57 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to two equivalent Ba, eight Mg, and two equivalent Hf atoms to form distorted MgBa2Hf2Mg8 cuboctahedra that share corners with twelve equivalent MgBa2Hf2Mg8 cuboctahedra, edges with four equivalent BaMg12 cuboctahedra, edges with four equivalent HfMg12 cuboctahedra, faces with two equivalent BaMg12 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, and faces with six equivalent MgBa2Hf2Mg8 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.34–3.39 Å. There are one shorter (3.34 Å) and one longer (3.36 Å) Mg–Hf bond lengths. In the second Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Hf atoms. There are one shorter (2.97 Å) and one longer (2.98 Å) Mg–Mg bond lengths. Both Mg–Hf bond lengths are 3.16 Å. In the third Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Hf atoms. Both Mg–Hf bond lengths are 3.19 Å. In the fourth Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Hf atoms. Both Mg–Hf bond lengths are 3.20 Å. Hf is bonded to twelve Mg atoms to form HfMg12 cuboctahedra that share corners with four equivalent HfMg12 cuboctahedra, corners with eight equivalent BaMg12 cuboctahedra, edges with eight equivalent MgBa2Hf2Mg8 cuboctahedra, faces with two equivalent HfMg12 cuboctahedra, faces with four equivalent BaMg12 cuboctahedra, and faces with four equivalent MgBa2Hf2Mg8 cuboctahedra.