Cotunnite is the natural mineral form of lead(II) chloride (PbCl2).

Cotunnite occurs near volcanoes: Vesuvius, Italy; Tarapacá, Chile; and Tolbachik, Russia.

[3] It was named for Domenico Cotugno (Cotunnius) (1736–1822), Italian physician and Professor of Anatomy.

[2][6] It occurs in association with galena, cerussite, anglesite and matlockite in the Caracoles, Chile.

At the Tolbachik volcano on the Kamchatka Peninsula, Russia it occurs with the rare to uncommon minerals tenorite, ponomarevite, sofiite, burnsite, ilinskite, georgbokite, chloromenite, halite, sylvite and native gold.