Materials Data on BaMg6Nb by Materials Project
BaMg6Nb 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 NbMg12 cuboctahedra, edges with eight equivalent MgBa2Mg8Nb2 cuboctahedra, faces with two equivalent BaMg12 cuboctahedra, faces with four equivalent MgBa2Mg8Nb2 cuboctahedra, and faces with four equivalent NbMg12 cuboctahedra. There are four shorter (3.38 Å) and eight longer (3.53 Å) Ba–Mg bond lengths. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to two equivalent Ba, eight Mg, and two equivalent Nb atoms to form MgBa2Mg8Nb2 cuboctahedra that share corners with twelve equivalent MgBa2Mg8Nb2 cuboctahedra, edges with four equivalent BaMg12 cuboctahedra, edges with four equivalent NbMg12 cuboctahedra, faces with two equivalent BaMg12 cuboctahedra, faces with two equivalent NbMg12 cuboctahedra, and faces with six equivalent MgBa2Mg8Nb2 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.28–3.32 Å. There are one shorter (3.36 Å) and one longer (3.40 Å) Mg–Nb bond lengths. In the second Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Nb atoms. There are one shorter (2.92 Å) and one longer (2.93 Å) Mg–Mg bond lengths. Both Mg–Nb bond lengths are 3.05 Å. In the third Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Nb atoms. Both Mg–Nb bond lengths are 3.07 Å. In the fourth Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Ba, six Mg, and two equivalent Nb atoms. Both Mg–Nb bond lengths are 3.06 Å. Nb is bonded to twelve Mg atoms to form NbMg12 cuboctahedra that share corners with four equivalent NbMg12 cuboctahedra, corners with eight equivalent BaMg12 cuboctahedra, edges with eight equivalent MgBa2Mg8Nb2 cuboctahedra, faces with two equivalent NbMg12 cuboctahedra, faces with four equivalent BaMg12 cuboctahedra, and faces with four equivalent MgBa2Mg8Nb2 cuboctahedra.