Materials Data on TaB2Mo3C2 by Materials Project

Abstract

TaMo3B2C2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ta3+ is bonded to one B3- and five C4- atoms to form distorted TaBC5 square pyramids that share corners with four equivalent TaBC5 square pyramids, edges with four equivalent TaBC5 square pyramids, and edges with four equivalent MoBC5 square pyramids. The Ta–B bond length is 2.74 Å. There are one shorter (2.20 Å) and four longer (2.21 Å) Ta–C bond lengths. There are three inequivalent Mo+3.67+ sites. In the first Mo+3.67+ site, Mo+3.67+ is bonded to one B3- and five C4- atoms to form distorted MoBC5 square pyramids that share corners with four equivalent MoBC5 square pyramids, edges with four equivalent TaBC5 square pyramids, and edges with four equivalent MoBC5 square pyramids. The Mo–B bond length is 2.73 Å. There are one shorter (2.19 Å) and four longer (2.21 Å) Mo–C bond lengths. In the second Mo+3.67+ site, Mo+3.67+ is bonded in a 1-coordinate geometry to six B3- and one C4- atom. There are four shorter (2.34 Å) and two longer (2.37 Å) Mo–B bond lengths. The Mo–C bond length is 2.08 Å. In the third Mo+3.67+ site, Mo+3.67+ is bonded in a 1-coordinate geometry to six B3- and one C4- atom. All Mo–B bond lengths are 2.32 Å. The Mo–C bond length is 2.16 Å. There are two inequivalent B3- sites. In the first B3- site, B3- is bonded in a 9-coordinate geometry to one Ta3+, six Mo+3.67+, and two equivalent B3- atoms. Both B–B bond lengths are 1.85 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to seven Mo+3.67+ and two equivalent B3- atoms. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to one Ta3+ and five Mo+3.67+ atoms to form a mixture of edge and corner-sharing CTaMo5 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second C4- site, C4- is bonded to four equivalent Ta3+ and two Mo+3.67+ atoms to form CTa4Mo2 octahedra that share corners with four equivalent CTa4Mo2 octahedra and edges with eight CTaMo5 octahedra. The corner-sharing octahedral tilt angles are 7°.