DOE OSTI2019
Nb4Mo11B20 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are two inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to twelve B+1.50- atoms to form a mixture of face and edge-sharing NbB12 cuboctahedra. There are a spread of Nb–B bond distances ranging from 2.42–2.49 Å. In the second Nb2+ site, Nb2+ is bonded to twelve B+1.50- atoms to form a mixture of face and edge-sharing NbB12 cuboctahedra. There are eight shorter (2.42 Å) and four longer (2.48 Å) Nb–B bond lengths. There are six inequivalent Mo2+ sites. In the first Mo2+ site, Mo2+ is bonded in a 7-coordinate geometry to seven B+1.50- atoms. There are a spread of Mo–B bond distances ranging from 2.30–2.54 Å. In the second Mo2+ site, Mo2+ is bonded in a 7-coordinate geometry to seven B+1.50- atoms. There are a spread of Mo–B bond distances ranging from 2.32–2.52 Å. In the third Mo2+ site, Mo2+ is bonded in a 7-coordinate geometry to seven B+1.50- atoms. There are a spread of Mo–B bond distances ranging from 2.31–2.52 Å. In the fourth Mo2+ site, Mo2+ is bonded in a 7-coordinate geometry to seven B+1.50- atoms. There are a spread of Mo–B bond distances ranging from 2.32–2.51 Å. In the fifth Mo2+ site, Mo2+ is bonded in a 7-coordinate geometry to seven B+1.50- atoms. There are a spread of Mo–B bond distances ranging from 2.32–2.51 Å. In the sixth Mo2+ site, Mo2+ is bonded to twelve B+1.50- atoms to form a mixture of face and edge-sharing MoB12 cuboctahedra. There are eight shorter (2.41 Å) and four longer (2.48 Å) Mo–B bond lengths. There are ten inequivalent B+1.50- sites. In the first B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to two equivalent Nb2+, five Mo2+, and two equivalent B+1.50- atoms. Both B–B bond lengths are 1.83 Å. In the second B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to two equivalent Nb2+, five Mo2+, and two equivalent B+1.50- atoms. Both B–B bond lengths are 1.83 Å. In the third B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to two equivalent Nb2+, five equivalent Mo2+, and two equivalent B+1.50- atoms. Both B–B bond lengths are 1.83 Å. In the fourth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to two equivalent Nb2+, five Mo2+, and two equivalent B+1.50- atoms. Both B–B bond lengths are 1.83 Å. In the fifth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to seven Mo2+ and two equivalent B+1.50- atoms. Both B–B bond lengths are 1.84 Å. In the sixth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to four equivalent Nb2+, two equivalent Mo2+, and three B+1.50- atoms. The B–B bond length is 1.85 Å. In the seventh B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to four equivalent Nb2+, two equivalent Mo2+, and three B+1.50- atoms. The B–B bond length is 1.85 Å. In the eighth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to four equivalent Nb2+, two equivalent Mo2+, and three B+1.50- atoms. In the ninth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to four equivalent Nb2+, two equivalent Mo2+, and three B+1.50- atoms. In the tenth B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to six Mo2+ and three B+1.50- atoms. The B–B bond length is 1.81 Å.