DOI: 10.17188/1674088
title: Materials Data on NaMg6BO7 by Materials Project

description: NaMg6BO7 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. Na is bonded to five O atoms to form NaO5 square pyramids that share a cornercorner with one MgO5 square pyramid, corners with four equivalent NaO5 square pyramids, and edges with four equivalent MgO6 octahedra. There are four shorter (2.12 Å) and one longer (2.24 Å) Na–O bond lengths. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share a cornercorner with one NaO5 square pyramid, corners with four equivalent MgO5 square pyramids, edges with four equivalent MgO6 octahedra, and edges with four equivalent MgO5 square pyramids. There are one shorter (2.03 Å) and four longer (2.12 Å) Mg–O bond lengths. In the second Mg site, Mg is bonded to five O atoms to form distorted MgO5 square pyramids that share corners with four equivalent MgO6 octahedra, corners with four equivalent MgO5 square pyramids, and edges with four equivalent MgO5 square pyramids. The corner-sharing octahedral tilt angles are 82°. There are one shorter (1.99 Å) and four longer (2.14 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded in a 4-coordinate geometry to four O atoms. There are a spread of Mg–O bond distances ranging from 2.04–2.61 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four equivalent MgO6 octahedra, edges with two equivalent NaO5 square pyramids, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 9–18°. There are a spread of Mg–O bond distances ranging from 2.09–2.16 Å. B is bonded in a distorted single-bond geometry to five O atoms. There is one shorter (1.39 Å) and four longer (2.15 Å) B–O bond length. There are five inequivalent O sites. In the first O site, O is bonded to one Na and five Mg atoms to form ONaMg5 octahedra that share corners with four equivalent ONaMg5 octahedra and edges with eight ONa2Mg2B2 octahedra. The corner-sharing octahedral tilt angles are 9°. In the second O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four equivalent ONa2Mg2B2 octahedra, corners with four equivalent OMg5 square pyramids, and edges with four equivalent OMg6 octahedra. The corner-sharing octahedral tilt angles are 81°. In the third O site, O is bonded in a 5-coordinate geometry to four equivalent Mg and one B atom. In the fourth O site, O is bonded to two equivalent Na, two Mg, and two equivalent B atoms to form ONa2Mg2B2 octahedra that share corners with six ONa2Mg2B2 octahedra, corners with two equivalent OMg5 square pyramids, and edges with six ONaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–20°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six ONa2Mg2B2 octahedra, edges with six ONaMg5 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 0–16°.