The Cdl2 and CdCl2 lattices layer structures

If a crystal breaks along a plane related to the lattice structure, the plane is called a cleavage plane. 

Other compounds crystalhzing with a Cdl2 lattice include MgBr2, Mgl2, Cal2, iodides of many J-block metals, and many metal hydroxides including Mg(OH)2 (the mineral brucite) in which the [OH] ions are treated as spheres for the purposes of structural description. 

The CdCl2 lattice is related to the Cdl2 layer-structure but with the Cl ions in a cubic close-packed arrangement. Examples of compounds adopting this structure are FeCl2 and C0CI2. Other layer structures include talc and mica (see Section 13.9). 

The structures of some high-temperature superconductors are also related to that of perovskite. Another mixed oxide lattice is that of spinel, MgAl204 (see Box 12.6). 

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