CRYSTAL-STRUCTURE OF 2 LIZARDITES, MG3SI2O5(OH)(4)

The crystal structure of the single layer lizardite, Mg(3)S(2)zO(5)(OH )(4) [space group Cm, Z = 2, a = 5.306(5), b = 9.186(8), c = 7.289(7)A ngstrom, beta = 90 degrees] and lizardite with equal number of basic s erpentine layers in alternate orientation [space group P31m, Z = 1, a = 5.301(5), c = 7.281(7)Angstrom], has been studied by X-ray analysis. In the first case Mg ions occupy two distinct positions along the z-a xis. In the second case, with the change in the orientation of octahed ral layer and the formation of closer contact between the neighboring layers in one of the two (mu or gamma) possible orientation, no buckli ng of Mg atomic plane is observed.