The crystal structure of MnS2 [hauerite a=6.1013(1) Å; u-parameter 0.40105(4) from Osorezan, Aomori], MnSe2 [a = 6.4275(2)Å; u-parameter 0.39358(2)], MnTe2 [a = 6.9513(1) Å; u-parameter 0.38554(2); space group Pa-3; Z=4] and FeS2 [pyrite a=5.4190(1)Å; u-parameter 0.38484(5) from Nagasaki] have been analysed by the single-crystal X-ray diffraction and refined yielding the R1 values of 0.0113, 0.0160, 0.0189 and 0.0181 using 354, 278, 318 and 165 unique reflections with Fo>2σ(Fo).
