Crystal structure of (C(9)H(17)N(2))(3)[Bi(2)I(9)]

Single crystals of tris­(2,3,4,6,7,8,9,10-octa­hydro­pyrimido[1,2-a]azepin-1-ium) tri-μ(2)-iodido-bis­[tri­iodido­bis­muth(III)], (C(9)H(17)N(2))(3)[Bi(2)I(9)], were prepared by a solvothermal method, heating a mixture of BiI(3), KI, 1,8-di­aza­bicyclo­[5.4.0]undec-7-ene (DBU) and ethanol at 443 K for six days. The asymmetric unit of the title compound, which crystallizes in the monoclinic space group P2(1)/c, contains one [Bi(2)I(9)](3−) anion and three protonated DBUH(+) moieties. The dinuclear [Bi(2)I(9)](3−) anions, which are composed of face-sharing BiI(6) (3−) octa­hedra, are packed in columns parallel to the [010] direction, and separated by protonated DBUH(+) moieties. The optical band gap of (C(9)H(7)N(2))(3)Bi(2)I(9) is 2.1 eV.