Summary: Some structural analogies found in tsumebite, vauquelinite, fornacite, and brackebuschite make it possible to place these secondary lead minerals in the same series with general formula Pb₂Me^II(Z)(XO₄)(YO₄), where Me^II is a bivalent cation as Cu²⁺ or Mn²⁺, Z is the hydroxyl group or the water molecule, X is S, Cr, or V, and Y is P, As, or V. Some crystallochemical considerations are developed in order to explain how the replacement of these elements affects the crystal structure in these substances.