Materials Data on Cr3(MoC2)2 by Materials Project

Abstract

Cr3(MoC2)2 is MAX Phase-like structured and crystallizes in the trigonal R3m space group. The structure is two-dimensional and consists of three Cr3(MoC2)2 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Mo4+ sites. In the first Mo4+ site, Mo4+ is bonded to six C4- atoms to form MoC6 octahedra that share corners with three equivalent CrC6 octahedra, edges with three equivalent CrC6 octahedra, and edges with six equivalent MoC6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.15 Å) and three longer (2.20 Å) Mo–C bond lengths. In the second Mo4+ site, Mo4+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Mo–C bond lengths are 2.10 Å. There are three inequivalent Cr+2.67+ sites. In the first Cr+2.67+ site, Cr+2.67+ is bonded in a trigonal non-coplanar geometry to three equivalent C4- atoms. All Cr–C bond lengths are 1.93 Å. In the second Cr+2.67+ site, Cr+2.67+ is bonded to six C4- atoms to form a mixture of corner and edge-sharing CrC6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (2.06 Å) and three longer (2.10 Å) Cr–C bond lengths. In the third Cr+2.67+ site, Cr+2.67+ is bonded to six C4- atoms to form CrC6 octahedra that share corners with three equivalent MoC6 octahedra, corners with three equivalent CrC6 octahedra, edges with three equivalent MoC6 octahedra, and edges with nine CrC6 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. There are three shorter (2.02 Å) and three longer (2.11 Å) Cr–C bond lengths. There are four inequivalent C4- sites. In the first C4- site, C4- is bonded to six Cr+2.67+ atoms to form a mixture of corner and edge-sharing CCr6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the second C4- site, C4- is bonded to six Cr+2.67+ atoms to form CCr6 octahedra that share corners with six CCr3Mo3 octahedra and edges with twelve CCr6 octahedra. The corner-sharing octahedra tilt angles range from 2–3°. In the third C4- site, C4- is bonded to three equivalent Mo4+ and three equivalent Cr+2.67+ atoms to form a mixture of corner and edge-sharing CCr3Mo3 octahedra. The corner-sharing octahedra tilt angles range from 2–3°. In the fourth C4- site, C4- is bonded to six Mo4+ atoms to form a mixture of corner and edge-sharing CMo6 octahedra. The corner-sharing octahedral tilt angles are 2°.