DOI: 10.17188/1291653
title: Materials Data on Mg7Cu2O9 by Materials Project

description: Mg7Cu2O9 is Caswellsilverite-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are seven 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 CuO6 octahedra, corners with four MgO6 octahedra, edges with three CuO6 octahedra, and edges with nine MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.14 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four MgO6 octahedra, edges with three CuO6 octahedra, and edges with nine MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.14 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four CuO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are four shorter (2.12 Å) and two longer (2.13 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with five MgO6 octahedra, edges with two equivalent CuO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.14 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four CuO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are four shorter (2.12 Å) and two longer (2.13 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two MgO6 octahedra, corners with four CuO6 octahedra, edges with two CuO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are a spread of Mg–O bond distances ranging from 2.10–2.12 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with five MgO6 octahedra, edges with two equivalent CuO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.14 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded to six O2- atoms to form CuO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with five MgO6 octahedra, edges with two equivalent CuO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Cu–O bond distances ranging from 2.12–2.16 Å. In the second Cu2+ site, Cu2+ is bonded to six O2- atoms to form CuO6 octahedra that share a cornercorner with one CuO6 octahedra, corners with five MgO6 octahedra, edges with two equivalent CuO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Cu–O bond distances ranging from 2.13–2.16 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Cu2+ atom to form OMg5Cu octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O2- site, O2- is bonded to four Mg2+ and two equivalent Cu2+ atoms to form OMg4Cu2 octahedra that share corners with six OMg4Cu2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third O2- site, O2- is bonded to four Mg2+ and two equivalent Cu2+ atoms to form OMg4Cu2 octahedra that share corners with six OMg4Cu2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fourth O2- site, O2- is bonded to five Mg2+ and one Cu2+ atom to form OMg5Cu octahedra that share corners with six OMg4Cu2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fifth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the sixth O2- site, O2- is bonded to four Mg2+ and two Cu2+ atoms to form OMg4Cu2 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg4Cu2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg4Cu2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the eighth O2- site, O2- is bonded to four Mg2+ and two equivalent Cu2+ atoms to form OMg4Cu2 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the ninth O2- site, O2- is bonded to four Mg2+ and two equivalent Cu2+ atoms to form a mixture of edge and corner-sharing OMg4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.