DOI: 10.17188/1687487
title: Materials Data on NaMg6Nb by Materials Project

description: NaMg6Nb is beta Cu3Ti-derived structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Na is bonded to ten Mg and two equivalent Nb atoms to form NaMg10Nb2 cuboctahedra that share corners with four equivalent MgNa2Mg10 cuboctahedra, corners with six equivalent NaMg10Nb2 cuboctahedra, edges with four equivalent NbNa2Mg10 cuboctahedra, edges with ten MgNa2Mg10 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, and faces with twelve MgNa2Mg10 cuboctahedra. There are a spread of Na–Mg bond distances ranging from 3.06–3.27 Å. Both Na–Nb bond lengths are 3.23 Å. There are eight inequivalent Mg sites. In the first Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Na, eight Mg, and two equivalent Nb atoms. There are a spread of Mg–Mg bond distances ranging from 3.00–3.40 Å. Both Mg–Nb bond lengths are 3.04 Å. In the second Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Na, eight Mg, and two equivalent Nb atoms. There are a spread of Mg–Mg bond distances ranging from 3.00–3.40 Å. Both Mg–Nb bond lengths are 3.04 Å. In the third Mg site, Mg is bonded to two equivalent Na and ten Mg atoms to form MgNa2Mg10 cuboctahedra that share corners with four equivalent NaMg10Nb2 cuboctahedra, corners with six equivalent MgNa2Mg10 cuboctahedra, edges with two equivalent NaMg10Nb2 cuboctahedra, edges with twelve MgNa2Mg8Nb2 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with six equivalent NbNa2Mg10 cuboctahedra, and faces with eight MgNa2Mg10 cuboctahedra. There are four shorter (3.15 Å) and three longer (3.16 Å) Mg–Mg bond lengths. In the fourth Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Nb atoms to form distorted MgNa2Mg8Nb2 cuboctahedra that share corners with four equivalent NbNa2Mg10 cuboctahedra, corners with fourteen MgNa2Mg8Nb2 cuboctahedra, edges with two equivalent NbNa2Mg10 cuboctahedra, edges with four equivalent NaMg10Nb2 cuboctahedra, edges with eight MgNa2Mg10 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, and faces with eight MgNa2Mg10 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.13–3.21 Å. There are one shorter (3.04 Å) and one longer (3.29 Å) Mg–Nb bond lengths. In the fifth Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Nb atoms to form distorted MgNa2Mg8Nb2 cuboctahedra that share corners with four equivalent NbNa2Mg10 cuboctahedra, corners with fourteen MgNa2Mg8Nb2 cuboctahedra, edges with two equivalent NbNa2Mg10 cuboctahedra, edges with four equivalent NaMg10Nb2 cuboctahedra, edges with eight MgNa2Mg10 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, and faces with eight MgNa2Mg10 cuboctahedra. Both Mg–Na bond lengths are 3.15 Å. There are a spread of Mg–Mg bond distances ranging from 3.13–3.21 Å. There are one shorter (3.04 Å) and one longer (3.29 Å) Mg–Nb bond lengths. In the sixth Mg site, Mg is bonded to ten Mg and two equivalent Nb atoms to form MgMg10Nb2 cuboctahedra that share corners with four equivalent NbNa2Mg10 cuboctahedra, corners with fourteen MgNa2Mg8Nb2 cuboctahedra, edges with two equivalent NbNa2Mg10 cuboctahedra, edges with eight MgNa2Mg10 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, faces with six equivalent NaMg10Nb2 cuboctahedra, and faces with eight MgNa2Mg10 cuboctahedra. There are two shorter (3.17 Å) and one longer (3.20 Å) Mg–Mg bond lengths. Both Mg–Nb bond lengths are 3.20 Å. In the seventh Mg site, Mg is bonded in a 12-coordinate geometry to two equivalent Na, eight Mg, and two equivalent Nb atoms. Both Mg–Mg bond lengths are 3.18 Å. Both Mg–Nb bond lengths are 3.04 Å. In the eighth Mg site, Mg is bonded to two equivalent Na, eight Mg, and two equivalent Nb atoms to form distorted MgNa2Mg8Nb2 cuboctahedra that share corners with four equivalent NbNa2Mg10 cuboctahedra, corners with fourteen MgNa2Mg8Nb2 cuboctahedra, edges with two equivalent NbNa2Mg10 cuboctahedra, edges with four equivalent NaMg10Nb2 cuboctahedra, edges with eight MgNa2Mg10 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, and faces with eight MgNa2Mg10 cuboctahedra. Both Mg–Mg bond lengths are 3.18 Å. There are one shorter (3.04 Å) and one longer (3.29 Å) Mg–Nb bond lengths. Nb is bonded to two equivalent Na and ten Mg atoms to form NbNa2Mg10 cuboctahedra that share corners with six equivalent NbNa2Mg10 cuboctahedra, corners with twelve MgNa2Mg8Nb2 cuboctahedra, edges with four equivalent NaMg10Nb2 cuboctahedra, edges with six MgNa2Mg8Nb2 cuboctahedra, faces with two equivalent NaMg10Nb2 cuboctahedra, faces with two equivalent NbNa2Mg10 cuboctahedra, and faces with twelve MgNa2Mg10 cuboctahedra.