Über Fluoride des einwertigen und des zweiwertigen Quecksilbers

On Fluorides of Univalent and Divalent Mercury For the first time Rb₂HgF₄ and Cs₂HgF₄, both colourless, have been obtained. From single crystal investigations they crystallize tetragonal in the K₂NiF₄-type of structure, space group I4/mrnm-D_4h¹⁷ (No. 139) with a = 455.6 pm, c = 1375.7 pm, Z = 2 for Rb₂HgF₄ and a = 462.5 pm, c = 1451.8 pm, Z = 2 for Cs₂HgF₄. The determination of the crystal structure of Hg₂F₂ confirmed the unit cell [1] with a = 367.00(4) pm, c = 1090.1(2) pm, Z = 2 space group I4/mrnm-D_4h¹⁷ (No. 139).