DOE OSTI2020
Nb3Se10Br3 crystallizes in the monoclinic P2_1/m space group. The structure is two-dimensional and consists of one Nb3Se10Br3 sheet oriented in the (1, 0, -1) direction. there are three inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded in a 8-coordinate geometry to six Se+1.20- and two Br1- atoms. There are a spread of Nb–Se bond distances ranging from 2.58–2.74 Å. Both Nb–Br bond lengths are 2.73 Å. In the second Nb5+ site, Nb5+ is bonded in a distorted hexagonal bipyramidal geometry to eight Se+1.20- atoms. There are a spread of Nb–Se bond distances ranging from 2.66–2.72 Å. In the third Nb5+ site, Nb5+ is bonded in a 8-coordinate geometry to six Se+1.20- and two Br1- atoms. There are a spread of Nb–Se bond distances ranging from 2.59–2.74 Å. There are one shorter (2.73 Å) and one longer (2.74 Å) Nb–Br bond lengths. There are twelve inequivalent Se+1.20- sites. In the first Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ atoms. In the second Se+1.20- site, Se+1.20- is bonded in a 4-coordinate geometry to two Nb5+, one Se+1.20-, and one Br1- atom. The Se–Se bond length is 2.39 Å. The Se–Br bond length is 3.14 Å. In the third Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two equivalent Nb5+ atoms. In the fourth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ atoms. In the fifth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ atoms. In the sixth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two equivalent Nb5+ atoms. In the seventh Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two equivalent Nb5+ atoms. In the eighth Se+1.20- site, Se+1.20- is bonded in a 4-coordinate geometry to two Nb5+, one Se+1.20-, and one Br1- atom. The Se–Se bond length is 2.39 Å. The Se–Br bond length is 3.14 Å. In the ninth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ atoms. In the tenth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two equivalent Nb5+ atoms. In the eleventh Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ and one Se+1.20- atom. In the twelfth Se+1.20- site, Se+1.20- is bonded in a 2-coordinate geometry to two Nb5+ and one Se+1.20- atom. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 1-coordinate geometry to one Nb5+ and one Se+1.20- atom. In the second Br1- site, Br1- is bonded in an L-shaped geometry to two equivalent Nb5+ atoms. In the third Br1- site, Br1- is bonded in a 1-coordinate geometry to one Nb5+ and one Se+1.20- atom. In the fourth Br1- site, Br1- is bonded in an L-shaped geometry to two equivalent Nb5+ atoms.