Lead Arsenite, Pb₃(AsO₃)₂

Lead Arsenite, Pb₃(AsO₃)₂, is obtained as a white precipitate on adding an arsenite solution to an alkaline lead solution. When dried in the air, it becomes grey and black, which is attributed to the reduction of the lead to suboxide. This salt is slightly soluble in water and easily soluble in caustic soda solution.

The pyroarsenite, 2PbO.As₂O₃ or Pb₂As₂O₅, is a white powder formed by decomposing neutral lead acetate solution with ammoniacal arsenious oxide solution. The pyroarsenite is also formed by the combination of arsenious oxide vapour with lead oxide.

The metarsenite PbO.As₂O₃ or Pb(AsO₂)₂ is formed from a hot saturated solution of arsenious oxide in ammonia, and a neutral lead salt solution. It forms microscopic prisms, very slightly soluble in water.