Crystal structure analysis and refinement of Kalabsha kaolinite (Al2Si2O5(OH)4)

The crystal structure of the kaolinite mineral from Kalabsha, Aswan, Egypt, has been investigated with a two-step procedure of the X-ray powder pattern-fitting. The unit cell is found to be triclinic, P1, a = 5.1577(15), b = 8.9417(23), c = 7.3967(40) Å, α = 91.672(5)°, β = 104.860(2) and γ = 89.898(2)°. The refinements of the non-hydrogen atomic positions showed a reliability factors R_WB = 0.037 and R_B = 0.0417. The average rotation angle in the tetrahedral layer in 10°.