Constantes cristallographiques de CuSe₂O₅, CuSeO₃ et Cu₂SeO₄

Crystal data of three compounds in the system SeO₂–CuO have been determined from X-ray single-crystal and powder studies. CuSe₂O₅ is monoclinic, space group Cc or C2/c, with a = 12.254 (5), b = 4.858 (3), c = 7.960 (3) Å, β = 110.7 (1)°, Z = 4. CuSeO₃ is monoclinic, space group P2₁/c, with a = 7.718 (2), b = 8.266 (3), c = 10.529 (3), β = 127.2 (2)°, Z = 8. Cu₂SeO₄ is cubic, space group P2₁3 or P4₂32, with a = 8.928 (3) Å, Z = 8. Powder diffraction data are given for all three compounds.