A Symmetric F−H−F Hydrogen Bond in Strontium Bifluoride, Sr[HF 2 ] 2

Single crystal X‐ray diffraction shows the hydrogen bond within the [F−H−F] − anion of Sr[HF 2 ] 2 to be symmetric with H−F bond lengths of 1.143(5) Å and an intramolecular F⋅⋅⋅F distance of 2.2826(18) Å. The [HF 2 ] − anion adopts crystallographic C 2 ‐symmetry, however, it is essentially linear with a F−H−F angle of 174(4)°. Solid‐state quantum chemical calculations agree with the experimental findings, showing a slightly bent F−H−F angle of 177.8°. The decomposition of Sr[HF 2 ] 2 to SrF 2 and HF is endothermic by +64 kJ/mol at room temperature. The bonding in the [F−H−F] − anion is clearly ionic both in the solid state and gas phase.