Boleite:: Resolution of the formula, KPb26Ag9Cu24Cl62 (OH)48

The crystal structure of boleite, K Pb-26 Ag-9 Cu-24 Cl-62 (OH)(48), a 15.288(2) Angstrom, V 3574(1) Angstrom (3), Pm (3) over barm, Z = 1, has been refined to an R-index of 2.2% based on 884 observed (5 sigma) reflections collected with MoK alpha X-radiation. A new site was resolved, and site-scattering refinement showed it to be occupied by a scattering species with 19 epfu (electrons per formula unit); this result is in accord with complete occupancy of this site by K. Potassium was detected by electron-microprobe analysis, but the amount determined is only similar to 50% of the amount indicated by site-scattering refinement. However, the refinement results show K to be disordered within a large cage in the structure, and the electron-beam bombardment probably induces rapid migration of K within the structure. Infrared spectroscopy shows that there is no H2O present in the structure. The H-sites were determined during refinement, and a sensible H-bonding scheme results.