DOE OSTI2020
Bi2Se4Cl7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Bi+3.50+ sites. In the first Bi+3.50+ site, Bi+3.50+ is bonded in a 7-coordinate geometry to seven Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.55–3.39 Å. In the second Bi+3.50+ site, Bi+3.50+ is bonded in a 6-coordinate geometry to seven Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.56–3.39 Å. In the third Bi+3.50+ site, Bi+3.50+ is bonded in a 7-coordinate geometry to seven Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.57–3.30 Å. In the fourth Bi+3.50+ site, Bi+3.50+ is bonded in a distorted octahedral geometry to six Cl1- atoms. There are a spread of Bi–Cl bond distances ranging from 2.57–3.13 Å. There are eight inequivalent Se sites. In the first Se site, Se is bonded in a 2-coordinate geometry to two Se and two Cl1- atoms. There are one shorter (2.35 Å) and one longer (2.37 Å) Se–Se bond lengths. There are one shorter (3.59 Å) and one longer (3.65 Å) Se–Cl bond lengths. In the second Se site, Se is bonded in a distorted T-shaped geometry to two Se and one Cl1- atom. There are one shorter (2.35 Å) and one longer (2.36 Å) Se–Se bond lengths. The Se–Cl bond length is 3.57 Å. In the third Se site, Se is bonded in a rectangular see-saw-like geometry to two Se and two Cl1- atoms. The Se–Se bond length is 2.35 Å. There are one shorter (3.13 Å) and one longer (3.32 Å) Se–Cl bond lengths. In the fourth Se site, Se is bonded in a distorted water-like geometry to two Se atoms. The Se–Se bond length is 2.36 Å. In the fifth Se site, Se is bonded in a 3-coordinate geometry to two Se and two Cl1- atoms. There are one shorter (3.54 Å) and one longer (3.66 Å) Se–Cl bond lengths. In the sixth Se site, Se is bonded in a 4-coordinate geometry to two Se and two Cl1- atoms. There are one shorter (2.36 Å) and one longer (2.37 Å) Se–Se bond lengths. There are one shorter (3.22 Å) and one longer (3.51 Å) Se–Cl bond lengths. In the seventh Se site, Se is bonded in a distorted L-shaped geometry to two Se atoms. In the eighth Se site, Se is bonded in a distorted T-shaped geometry to two Se and one Cl1- atom. The Se–Cl bond length is 3.45 Å. There are fourteen inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to two Bi+3.50+ and one Se atom. In the second Cl1- site, Cl1- is bonded in a distorted trigonal non-coplanar geometry to three Bi+3.50+ atoms. In the third Cl1- site, Cl1- is bonded in a 3-coordinate geometry to two Bi+3.50+ and one Se atom. In the fourth Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two Bi+3.50+ and one Se atom. In the fifth Cl1- site, Cl1- is bonded in a single-bond geometry to one Bi+3.50+ and two Se atoms. In the sixth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to two Bi+3.50+ atoms. In the seventh Cl1- site, Cl1- is bonded in a 2-coordinate geometry to three Bi+3.50+ atoms. In the eighth Cl1- site, Cl1- is bonded in a distorted water-like geometry to two Bi+3.50+ atoms. In the ninth Cl1- site, Cl1- is bonded in a bent 120 degrees geometry to two Bi+3.50+ atoms. In the tenth Cl1- site, Cl1- is bonded in a 1-coordinate geometry to two Bi+3.50+ and one Se atom. In the eleventh Cl1- site, Cl1- is bonded in a single-bond geometry to two Bi+3.50+ atoms. In the twelfth Cl1- site, Cl1- is bonded in a distorted water-like geometry to two Bi+3.50+ atoms. In the thirteenth Cl1- site, Cl1- is bonded in a single-bond geometry to one Bi+3.50+ and two Se atoms. In the fourteenth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Bi+3.50+ and two Se atoms.