Lewis Acid Base Reactions between Boron Trifluoride and Complex Oxoanions as a Versatile Access to Fluorooxoanions: Synthesis of Sodium (Trifluoroborato)sulfate

Na₂SO₄BF₃, synthesized in a closed vessel from BF₃ and Na₂SO₄ at 603 K, crystallizes in the triclinic space group P$bar{1}$ (a = 6.6033(2), b = 6.6328(2), c = 6.6349 (1) Å, α = 84.542(2), β = 84.458(1) and γ = 65.762(1)°). The novel fluorooxo anion [SO₄BF₃]^2– displays a structure similar to the disulfate anion S₂O₇^2–. Heating the title compound in the absence of BF₃ in the gas phase leads to decomposition even at 553 K, which is below the temperature of synthesis under BF₃ pressure.