Extending the mineralogy of U 6+ (V.): Hydrogen bonding in pseudojohannite – a well-ordered structure with zippeite-type sheets and Cu II in the interlayer

Newcrystallographic data are reported for pseudojohannite, Cu 3 (OH) 2 (UO 2 ) 4 O 4 (SO 4 ) 2 (H 2 O) 12 , from the type locality Jchymov, Czech Republic.The structure refinement is based on a dataset collected with high redundancy (8.62) using a brilliant X-ray microfocus source, which provided sufficient quality to localize hydrogen atoms from difference Fourier maps.The studied pseudojohanite crystal is triclinic at 100K, with the space group P-1, with a = 8.6697(4), b = 8.8712(5), c = 9.9825(6) , = 71.775(6), = 70.663(5), = 76.011(5), with V = 679.88(7) 3 and Z = 1.The final refinement converged to R 1 = 0.0198 for 6029 unique reflections with I > 3(I) and wR 2 = 0.0699 for all 6924 reflections.The bond-valence analysis for the structure and the determined positions of H atoms provided complete information on the nature of bonding between the (UO 2 ) 4 O 4 (SO 4 ) 2 structural units and the interlayer complex in pseudojohannite.In sum, there are eight transformer H 2 O groups, four non-transformer H 2 O (two of which are not directly linked to any metal cation sites), and two OH -groups.The structure formula of pseudojohannite can be written as Cu 3 (H 2 3 O) 8 (H 2 4 O) 2 (OH) 2 (UO 2 ) 4 O 4 (SO 4 ) 2 (H 2 4 O) 2 (Z = 1).Pseudojohannite represents a well-ordered triclinic zippeite-type structure.