The First Antimony Borosulfates Unveil a Modular System M^IIIM^I[B(SO₄)₂]₄ (M^III=Bi³⁺, Sb³⁺, Lu³⁺; M^I=H₃O⁺, NO<sub>2</su

Recently we reported the synthesis and characterization of Bi(H₃O)[B(SO₄)₂]₄, at that time representing only the second tectosilicate analogous borosulfate. Inspired by this structure type, we herein present the first modular system within borosulfate chemistry. M^IIIM^I[B(SO₄)₂]₄ (M^III=Bi³⁺, Sb³⁺, Lu³⁺; M^I=H₃O⁺, NO₂ ⁺, Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) were synthesised under solvothermal conditions and show a large variability towards their mono- and trivalent cation while retaining the same three-dimensional anionic network. Based on their combination, the titled compounds crystallize in the tetragonal space groups I <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:mover><mml:mn>4</mml:mn> <mml:mo>‾</mml:mo></mml:mover> <mml:annotation>${\bar{4}}$</mml:annotation> </mml:semantics> </mml:math> (no. 82), P <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:mover><mml:mn>4</mml:mn> <mml:mo>‾</mml:mo></mml:mover> <mml:annotation>${\bar{4}}$</mml:annotation> </mml:semantics> </mml:math> (no. 81) and the monoclinic space group C2 (no. 5) all connected via group-subgroup relations. Our initial characterization includes single-crystal as well as powder X-ray diffraction, vibrational spectroscopy and thermal analysis of the new compounds.