It is made by treating lead(II) oxide with acetic acid. Like other lead compounds, it is toxic. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate Pb(CH3COO)2·3H2O, a colourless or white efflorescent monoclinic crystalline substance. The substance is used as a reagent to make other lead compounds and as a fixative for some dyes. In low concentrations, it is the principal active ingredient in progressive types of hair colouring dyes. Formula C4H12O7Pb Molar mass 379.333 g/mol CAS Number 6080-56-4 Density 2.550 g/cm3 Purity/Grade ≥99% (ACS Reagent) Appearance Solid Melting point/freezing point 75°C (167°F) – dec.