DOI: 10.17188/1681904
title: Materials Data on KRbMg30O31 by Materials Project

description: RbKMg30O31 crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. Rb1+ is bonded to six O2- atoms to form RbO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are one shorter (2.38 Å) and five longer (2.42 Å) Rb–O bond lengths. K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are four shorter (2.38 Å) and one longer (2.67 Å) K–O bond lengths. There are ten inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with two equivalent MgO6 octahedra, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Mg–O bond distances ranging from 1.95–2.34 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 square pyramids that share corners with four equivalent MgO6 octahedra, corners with four equivalent MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are one shorter (1.96 Å) and four longer (2.12 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.03–2.27 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent RbO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 1.88–2.25 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, edges with eight MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–12°. There are a spread of Mg–O bond distances ranging from 2.15–2.21 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with nine MgO6 octahedra, and edges with three MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Mg–O bond distances ranging from 2.14–2.20 Å. In the seventh Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 square pyramids that share corners with four MgO6 octahedra, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–11°. There are a spread of Mg–O bond distances ranging from 1.93–2.14 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, an edgeedge with one RbO6 octahedra, edges with nine MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–12°. There are a spread of Mg–O bond distances ranging from 2.12–2.25 Å. In the ninth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with ten MgO6 octahedra, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 2–8°. There are a spread of Mg–O bond distances ranging from 2.11–2.29 Å. In the tenth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one RbO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–12°. There are a spread of Mg–O bond distances ranging from 2.14–2.22 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with four ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the second O2- site, O2- is bonded to one Rb1+ and five Mg2+ atoms to form ORbMg5 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the third O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form a mixture of distorted edge and corner-sharing OKMg5 octahedra. The corner-sharing octahedral tilt angles are 6°. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the fifth O2- site, O2- is bonded to one Rb1+ and five Mg2+ atoms to form a mixture of edge and corner-sharing ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the sixth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 1–17°. In the seventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve OKMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. In the eighth O2- site, O2- is bonded to one K1+ and five Mg2+ atoms to form OKMg5 octahedra that share corners with six ORbMg5 octahedra and edges with eleven OMg6 octahedra. The corner-sharing octahedra tilt angles range from 3–24°. In the ninth O2- site, O2- is bonded to one Rb1+ and five Mg2+ atoms to form ORbMg5 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 3–8°. In the tenth O2- site, O2- is bonded to six Mg2+ atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 3–14°. In the eleventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 1–8°.