_Lead, fluoride_, PbF2, is a white powder obtained by precipitating a lead salt with a soluble fluoride; it is sparingly soluble in water but readily dissolves in hydrochloric and nitric acids. A chloro-fluoride, PbClF, is obtained by adding sodium fluoride to a solution of lead chloride. Lead bromide, PbBr2, a white solid, and lead iodide, PbI2, a yellow solid, are prepared by precipitating a lead salt with a soluble bromide or iodide; they resemble the chloride in solubility. Entry: A
_Lead Borates._--By fusing litharge with boron trioxide, glasses of a composition varying with the proportions of the mixture are obtained; some of these are used in the manufacture of glass. The borate, Pb2B6O11·4H2O, is obtained as a white precipitate by adding borax to a lead salt; this on heating with strong ammonia gives PbB2O4·H2·O, which, in turn, when boiled with a solution of boric acid, gives PbB4O7·4H2O. Entry: A