The formulas for the basic sulfates of lead have been checked or established. The phase diagram for melts of and shows the compounds: , , and . A wet method of preparation leads to the compounds: , , and a hydrous compound tentatively assigned the formula: . X‐ray methods of analysis support these formulas. X‐ray diffraction patterns have been recorded for these compounds for use in identification work. The thermal decomposition products of and the hydrous compound have been shown to be a mixture of and in each case.