gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1996.060.400.04 Mineralogy The Stabilities of Secondary Tin Minerals. Part 2*: The Hydrolysis of Tin(II) Sulphate and the Stability of Sn3O(OH)2SO4 Edwards R. School of Chemical and Physical Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK Gillard R. D. Department of Chemistry, University of Wales, Cardiff, P.O.Box 912, Cardiff CF1 3TB, UK Williams P. A. School of Chemistry, University of Western Sydney, Nepean, P.O.Box 10, Kingswood, NSW 2750, Australia

Part 1: Edwards, R., Gillard, R.D. and Williams, P.A. (1992) Mineral. Mag., 56, 221-6.

 6 1996 60 400 427 432 27 3 1995 2 5 1995 Copyright © 1996, The Mineralogical Society 1996 Abstract

Tritin(II)dihydroxyoxosulphate, Sn3O(OH)2SO4, is a rare corrosion product found on the surfaces of certain tin alloys. A new synthesis based on the hydrolysis of SnSO4 is described. The stability constant determination of Sn3O(OH)2SO4,s, at 298.2K and 105Pa is determined using direct measurements via electrodes, of the activities of tin(II) and sulphate ions. ΔfG0(298.2K) is equal to −1563.1 ± 0.9 KJ mol−1.

 Keywords tin minerals stability tritin(II) dihydroxyoxosulphate