DOI: 10.17188/1716847
title: Materials Data on Mg30CrCO32 by Materials Project

description: Mg30CrCO32 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are eight 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 CrO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.11–2.15 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.07–2.17 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.13 Å) and two longer (2.15 Å) Mg–O bond lengths. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.12 Å) and two longer (2.17 Å) Mg–O bond lengths. 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 CrO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–14°. There are a spread of Mg–O bond distances ranging from 2.10–2.19 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.11–2.17 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CrO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are four shorter (2.12 Å) and two longer (2.16 Å) Mg–O bond lengths. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.10–2.16 Å. Cr2+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four equivalent MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.95 Å) and four longer (2.09 Å) Cr–O bond lengths. C2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All C–O bond lengths are 2.17 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded to five Mg2+ and one Cr2+ atom to form OMg5Cr octahedra that share corners with six OMg5Cr octahedra, edges with ten OMg5Cr octahedra, and edges with two equivalent OMg4Cr square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the second O2- site, O2- is bonded to five Mg2+ and one C2+ atom to form OMg5C octahedra that share corners with six OMg5C octahedra, corners with two equivalent OMg4Cr square pyramids, and edges with ten OMg5C octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third 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 0–1°. Both O–Mg bond lengths are 2.17 Å. 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 0–2°. In the fifth 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 0–1°. There are two shorter (2.12 Å) and two longer (2.17 Å) O–Mg bond lengths. 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 0–2°. There are two shorter (2.14 Å) and two longer (2.15 Å) O–Mg bond lengths. In the seventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with eleven OMg5Cr octahedra, and an edgeedge with one OMg4Cr square pyramid. The corner-sharing octahedra tilt angles range from 0–2°. In the eighth O2- site, O2- is bonded to four equivalent Mg2+ and one Cr2+ atom to form OMg4Cr square pyramids that share corners with eight OMg5C octahedra, a cornercorner with one OMg4Cr square pyramid, and edges with eight OMg5Cr octahedra. The corner-sharing octahedra tilt angles range from 8–81°. In the ninth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg4Cr square pyramids, and edges with twelve OMg5Cr octahedra. The corner-sharing octahedra tilt angles range from 0–1°. 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 0–1°. In the eleventh 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 0–1°. The O–Mg bond length is 2.11 Å. In the twelfth 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 0–1°. There are a spread of O–Mg bond distances ranging from 2.11–2.17 Å.