DOE OSTI2020
NbMoSe4(NbSe2)2 is Molybdenite-derived structured and crystallizes in the monoclinic Pm space group. The structure is two-dimensional and consists of one NbMoSe4 sheet oriented in the (0, 0, 1) direction and one NbSe2 sheet oriented in the (0, 0, 1) direction. In the NbMoSe4 sheet, Nb+4.67+ is bonded to six Se2- atoms to form distorted NbSe6 pentagonal pyramids that share edges with two equivalent NbSe6 pentagonal pyramids and edges with four equivalent MoSe6 pentagonal pyramids. There are four shorter (2.61 Å) and two longer (2.63 Å) Nb–Se bond lengths. Mo2+ is bonded to six Se2- atoms to form distorted MoSe6 pentagonal pyramids that share edges with two equivalent MoSe6 pentagonal pyramids and edges with four equivalent NbSe6 pentagonal pyramids. There are two shorter (2.57 Å) and four longer (2.58 Å) Mo–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Nb+4.67+ and two equivalent Mo2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Nb+4.67+ and one Mo2+ atom. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Nb+4.67+ and one Mo2+ atom. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Nb+4.67+ and two equivalent Mo2+ atoms. In the NbSe2 sheet, there are two inequivalent Nb+4.67+ sites. In the first Nb+4.67+ site, Nb+4.67+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are four shorter (2.62 Å) and two longer (2.63 Å) Nb–Se bond lengths. In the second Nb+4.67+ site, Nb+4.67+ is bonded to six Se2- atoms to form distorted edge-sharing NbSe6 pentagonal pyramids. There are four shorter (2.62 Å) and two longer (2.63 Å) Nb–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Nb+4.67+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Nb+4.67+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Nb+4.67+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Nb+4.67+ atoms.