Lead Tetrafluoride, PbF₄

Lead Tetrafluoride, PbF₄, was prepared by Brauner, in an impure state, by adding potassium hydrogen plumbifluoride, K₃HPbF₈, to cold concentrated sulphuric acid. Hydrogen fluoride gas escapes, whilst a yellow solution is formed, and then a penetrating vapour is evolved which is thought to be lead tetrafluoride. Gradually, however, the liquid becomes gelatinous, and then probably contains the tetrafluoride in a colloidal state; whilst heating it to 100°-110° C. causes a yellow powder to separate, which is believed to be a third modification of the tetrafluoride, since it liberates iodine from potassium iodide solution, gives lead dioxide with water, and dissolves in hydrofluoric acid forming hydrofluoplumbic acid.