The structure parameters of the wurtzite type compounds Sic-2H and ZnO were determined using X-ray intensities from single crystals collected with an automatic single crystal diffractometer. The lattice constants and the u-values are a = 3.079 A ̊, c = 5.053 A ̊, u = 0.3760 for Sic-2H and a = 3.253 A ̊, c = 5.213 A ̊, u = 0.3820 for ZnO. The final reliability values for refinements with anisotropic temperature factors are equal to R = 0.032 for Sic-2H and R = 0.024 for ZnO. © 1979.