Abstract
Exceptionally large crystals of posnjakite, Cu(4)SO(4)(OH)(6)(H(2)O), formed during corrosion of a Swagelock(tm) Snubber copper gasket within the MX1 beamline at the ANSTO-Melbourne, Australian Synchrotron. The crystal structure was solved using synchrotron radiation to R (1) = 0.029 and revealed a structure based upon [Cu(4)(OH)(6)(H(2)O)O] sheets, which contain Jahn-Teller-distorted Cu octa-hedra. The sulfate tetra-hedra are bonded to one side of the sheet via corner sharing and linked to successive sheets via extensive hydrogen bonds. The sulfate tetra-hedra are split and rotated, which enables additional hydrogen bonds.