Bismuth+oxychloride

=Bismuth oxychloride= is a chemical compound of bismuth, oxygen, and chlorine, with the formula BiOCl. It exists in nature as the mineral bismoclite which is part of the matlockite mineral group.

Structure
BiOCl structure

BiOCl crystallises in the tetragonal space group P4/nmm. The crystal structure can be thought of as consisting of layers of Cl−, Bi3+ and O2− ions, in the order Cl-Bi-O-Bi-Cl-Cl-Bi-O-Bi-Cl.

The bismuth atoms adopt a distorted square antiprismatic coordination geometry, with four chlorine atoms forming one of the square faces, each at a distance of 3.06 Å from Bi, and four oxygen atoms forming the other square face, each at a distance of 2.32 Å from Bi.

The oxygen atoms are tetrahedrally coordinated by four bismuth atoms.

Reactions
When BiOCl is heated above 600 °C, it forms Bi24O31Cl10, which can be thought of as Bi24O36 (i.e. Bi2O3) with 5 of the 36 oxygen atoms replaced by 2 chlorine atoms each.[3]

It is formed during the reaction of bismuth chloride with water.

Uses
It is used in [|cosmetics].