The equivalent weight with respect to lead is (148.8/0.5 = 297,6) g mineral/ mol Pb²⁺.

Since there is 5 times as much lead (in moles) as chloride in the mineral, a mineral portion of (5x297.6 = 1488) g should be taken to contain 5.0 mol Pb²⁺ and accordingly 1.0 mol Cl^- .

Charges on 5Pb²⁺ , 1Cl^- og xAsO₄^3- must match. It gives us x = 3 and the empirical formula Pb₅Cl(AsO₄)₃. The molar mass corresponding to 1 mole of this formula is 1488 g/mol; accordingly the mineral contains no water of crystallisation. The mineral is called Mimetesite.

The empirical formula of the mineral, Mimetesite is Pb₅Cl(AsO₄)₃.