Refinement of the crystal structure of botallackite

The crystal structure of botallackite, Cu 2 (OH) 3 Cl, monoclinic, a = 5.717(1), b = 6.126(1), c = 5.636(1)Å, β = 93.07(1)°, V = 197.06(5)Å 3 , space group P 2 1 / m , Z = 1, has been refined to an R index of 3.8% for 350 observed (4 σ ) reflections, measured with Mo- Kα X-radiation on an automatic four-circle diffractometer. The structure consists of sheets of edge-sharing Cu ϕ 6 ( ϕ = unspecified anion) octahedra of composition Cu 2 (OH) 3 Cl; these sheets are // {100}, and are joined by hydrogen bonding between oxygen and chlorine anions, thus accounting for the perfect {100} cleavage and the platy habit of botallackite.