Synthesis and crystal structures of Cd(OH)Cl and Cu(OH)Cl and relationship to brucite type

Synthesis of single crystals of Cd(OH)CI and Cu(OH)CI allowed us to revise the structure of these hydroxychlorides and confirm their space group: P6(3)mc (R = 0.041; R-w = 0.050) for Cd(OH)CI and P2(1)/c (R = 0.051; R-w = 0.069) for Cu(OH)CI. Positions of hydrogen atoms mere determined and an hypothesis of hydrogen bonds is discussed in relation to the infrared spectra, A comparison of the structures shows that an isomorphism is not possible between the two compounds, due to the important Jahn-Teller effect of divalent copper. On the other hand, a structural relationship exists between Cd(OH)CI and beta-Cd(OH)(2), which belongs to the brucite-type family. (C) 2000 Academic Press.