The crystal structure ofchloroxiphite, Pb₃ CuO₂ (OH)₂ Cl₂, from Merehead Quarry (monoclinic, P2₁/m, a = 6.6972(8), b = 5.7538(5), c = 10.4686(14) Å, β = 97.747(10)°, V = 399.72(8) ų) has been refined to R₁ = 0.041. The structure contains three symmetrically unique Pb sites and one Cu site. The strong distortion ofthe Pb²⁺ coordination polyhedra is due to the stereoactivity ofthe s² lone electron pairs on the Pb²⁺ cations. The Cu-site is coordinated by four OH^- groups to form an almost planar Cu(OH)₄ square that is complemented by two apical Cl^- anions, forming an elongated [Cu(OH)₄Cl₂] octahedron. Because ofthe large size and variability ofcoordination polyhedra around Pb²⁺ cations and the strength ofthe Me-O bonds in comparison to the Me-Cl bonds (Me = metal), it is convenient to describe the structure ofchloroxiphite in terms of oxocentred OPb₄ tetrahedra. The O1 atom is tetrahedrally coordinated by four Pb²⁺ cations forming relatively short and strong O-Pb bonds. The OPb₄ tetrahedra link together via common edges to form [O₂Pb₃]²⁺ double chains. The difference between chloroxiphite and other natural oxyhalides is the presence of Cu²⁺ cations which form an independent structural unit that links to units formed by OPb₄ tetrahedra. In this sense, chloroxiphite can be considered as a modular structure consisting ofboth strong cation- and anion-centred units.