The First Bismuth Borosulfates Comprising Oxonium and a Tectosilicate-Analogous Anion.

Abstract

The first bismuth borosulfate (H3O)Bi[B(SO4)2]4 is only the second featuring a three‐dimensional anion, the first tectosilicate‐analogous borosulfate synthesised solvothermally without a precursor (from Bi(NO3)3⋅5 H2O and B(OH)3 in oleum); moreover, it is the first comprising two differently charged cations and crystallises in a new structure type in space group I4‾ (no. 82) (a=11.857(1), c=8.149(1) Å, 1947 refl., 111 param., wR2=0.037), confirmed by a second harmonic generation (SHG) measurement. The B(SO4)4 supertetrahedra are connected via all four sulfate tetrahedra resulting in a three‐dimensional anion with both H3O+ and Bi3+ cations in channels. Additionally, the crystal structure of a further bismuth borosulfate, Bi2[B2(SO4)6], is elucidated crystallising isotypically to the rare‐earth borosulfates R2[B2(SO4)6] in space group C2/c (No. 15) (a=13.568(2), b=11.490(2), c=11.106(2) Å, 3127 refl., 155 param., wR2=0.035). Moreover, the optical and thermal properties of both compounds are discussed.