DOI: 10.17188/1656245
title: Materials Data on RbHfMg14O15 by Materials Project

description: RbMg14HfO15 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. Rb is bonded in a 5-coordinate geometry to five O atoms. There are a spread of Rb–O bond distances ranging from 2.30–2.80 Å. There are ten inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 octahedra, edges with ten MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 1.96–2.29 Å. In the second Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with two equivalent HfO6 octahedra, corners with four MgO5 square pyramids, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are a spread of Mg–O bond distances ranging from 2.01–2.31 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with seven MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 2–13°. There are a spread of Mg–O bond distances ranging from 2.16–2.24 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent HfO6 octahedra, edges with five MgO6 octahedra, and edges with four MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–9°. There are a spread of Mg–O bond distances ranging from 2.13–2.30 Å. In the fifth Mg site, Mg is bonded in a distorted square co-planar geometry to four O atoms. There are a spread of Mg–O bond distances ranging from 2.08–2.55 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, edges with two equivalent HfO6 octahedra, edges with six MgO6 octahedra, and edges with four equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.09–2.30 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four MgO6 octahedra, edges with eight MgO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 3–10°. There are a spread of Mg–O bond distances ranging from 1.97–2.26 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent HfO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of Mg–O bond distances ranging from 2.08–2.24 Å. In the ninth Mg site, Mg is bonded to five O atoms to form MgO5 square pyramids that share corners with two equivalent MgO6 octahedra, corners with four MgO5 square pyramids, an edgeedge with one HfO6 octahedra, and edges with seven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 5–14°. There are a spread of Mg–O bond distances ranging from 2.12–2.24 Å. In the tenth 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, an edgeedge with one HfO6 octahedra, edges with nine MgO6 octahedra, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 4–16°. There are a spread of Mg–O bond distances ranging from 2.12–2.35 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent HfO6 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 Hf–O bond distances ranging from 2.10–2.22 Å. There are eleven inequivalent O sites. In the first O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with four OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the second O site, O is bonded to one Rb and five Mg atoms to form distorted ORbMg5 octahedra that share corners with four ORbMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedral tilt angles are 10°. In the third O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with ten OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–8°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the sixth O site, O is bonded to two equivalent Rb and four Mg atoms to form distorted ORb2Mg4 octahedra that share corners with six OMg6 octahedra and edges with ten ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–32°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with ten ORbMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the ninth O site, O is bonded to four Mg and two equivalent Hf atoms to form OHf2Mg4 octahedra that share corners with six OMg6 octahedra and edges with twelve OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the tenth O site, O is bonded to one Rb and five Mg atoms to form distorted ORbMg5 octahedra that share corners with six ORbMg5 octahedra and edges with eleven OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–19°. In the eleventh O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six ORbMg5 octahedra and edges with eleven OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–16°.