The First Bismuth Borosulfates Comprising Oxonium and a Tectosilicate‐Analogous Anion

The first bismuth borosulfate (H(3)O)Bi[B(SO(4))(2)](4) is only the second featuring a three‐dimensional anion, the first tectosilicate‐analogous borosulfate synthesised solvothermally without a precursor (from Bi(NO(3))(3)⋅5 H(2)O 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 I [Formula: see text] (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(SO(4))(4) supertetrahedra are connected via all four sulfate tetrahedra resulting in a three‐dimensional anion with both H(3)O(+) and Bi(3+) cations in channels. Additionally, the crystal structure of a further bismuth borosulfate, Bi(2)[B(2)(SO(4))(6)], is elucidated crystallising isotypically to the rare‐earth borosulfates R(2)[B(2)(SO(4))(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.