Hostname: page-component-8448b6f56d-t5pn6 Total loading time: 0 Render date: 2024-04-18T09:20:19.326Z Has data issue: false hasContentIssue false

The aqueous chemistry of uranium minerals. 4. Schröckingerite, grimselite, and related alkali uranyl carbonates

Published online by Cambridge University Press:  05 July 2018

Timothy J. O'Brien
Affiliation:
Department of Inorganic Chemistry, University College, PO Box 78, Cardiff CF1 1XL
Peter A. Williams
Affiliation:
Department of Inorganic Chemistry, University College, PO Box 78, Cardiff CF1 1XL

Abstract

Using solution techniques, ΔG°f(298.2k) has been calculated for schröckingerite, NaCa3UO2(CO3)3 SO4F · 10H2O, and grimselite, NaK3UO2(CO3)3 · H2O. The values are −8077.3 ±8.7 and −4051.3 ±1.8 kJ mol−1 respectively. ΔH°f(298.2k) for grimselite is −4359.0 ± 1.8 kJ mol−1. An estimate for ΔG°f of the synthetic compound Na4UO2(CO3)3(s) using previously published equilibria has been made, −3720.0±9.7 kJ mol−1. The results have been used to reconstruct the chemical environments in which these and related compounds can form. Grimselite is only stable at relatively high activities of K(aq)+ and the alkali metal carbonates containing only potassium or sodium ions have not been reported to occur naturally. This is most probably due to their relatively high solubility in water. Schröckingerite can form from solutions which are more than saturated with respect to calcite and fluorite. The close relationship of schröckingerite with gypsum, observed frequently in the field, is evident from synthetic and solution studies.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1983

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alwan, A.K. (1980) The Chemistry of Formation of Some Mineral Species. Ph.D. thesis, University of Wales.Google Scholar
Alwan, A.K. and Williams, P.A. (1979) Transition Metal Chem. 4, 128–32.CrossRefGoogle Scholar
Alwan, A.K. and Williams, P.A. (1980) Mineral. Mag. 43, 665–7.CrossRefGoogle Scholar
Bachelet, M., Cheylan, E., Douis, and Goulette (1954) Bull. Soc. Chim. Fr. 173–9.Google Scholar
Baes, C.F., and Mesmer, R.E. (1976) The Hydrolysis of Cations. John Wiley and Sons.Google Scholar
Barczak, U.J. (1966) Am. Mineral. 51, 929–30.Google Scholar
Blake, C.A., Coleman, C.F., Brown, K.B., Hill, D.G., Lowrie, R.S., and Schmitt, J.M. (1956) J. Am. Chem. Soc. 78, 5978–83.CrossRefGoogle Scholar
Frondel, C. (1958) Systematic Mineralogy of Uranium and Thorium. U.S. Geol. Surv. Bull. 1064.Google Scholar
Fuger, J., and Oetting, F.L. (1976) The Chemical Thermodynamics of Actinide Elements and Compounds. Int. Atomic Energy Agency.Google Scholar
Jaffe, H.W., Sherwood, A.M., and Peterson, M.J. (1948) Am. Mineral. 33, 152–7.Google Scholar
Kielland, J. (1937) J. Am. Chem. Soc. 59, 1675–8.CrossRefGoogle Scholar
Krauskopf, K.B. (1979) Introduction to Geochemistry. 2nd edn. McGraw-Hill Kogakusha.Google Scholar
Langmuir, D. (1978) Geochim. Cosmochim. Acta, 42, 547–69.CrossRefGoogle Scholar
Mazzi, F., and Rinaldi, F. (1960) Acta Crystallogr. 13, 1139.Google Scholar
Mazzi, F., and Rinaldi, F. (1961) Period. Mineral. 30, 1–21.Google Scholar
O'Brien, T. J., and Williams, P.A. (1981) Inorg. Nucl. Chem. Letters, 17, 105–7.CrossRefGoogle Scholar
Perrin, D.D., and Sayce, I.G. (1967) Talanta, 14, 833–42.CrossRefGoogle Scholar
Reardon, E.J., and Langrnuir, D. (1976) Geochim. Cosmochim. Acta, 40, 549–54.CrossRefGoogle Scholar
Robie, R.A., Hemingway, B.S., and Fisher, J.R. (1978) Thermodynamic Properties of Minerals and Related Substances at 298.15 K and 1 Bar (10s Pascals) Pressure and at Higher Temperatures. U.S. Geol. Surv. Bull. 1452.Google Scholar
Ross, V. (1955) Am. Mineral. 40, 515–19.Google Scholar
Schrauf, A. (1873) Tschermaks Mineral. Petrogr. Mitt. 3, 137–8.Google Scholar
Smith, R.M., and Martell, A.E. (1975) Critical Stability Constants, Plenum Press.CrossRefGoogle Scholar
Truesdell, A.H., and Jones, B.F. (1974) J. Res. U.S. Geol. Surv. 2, 233–48.Google Scholar
Walenta, K. (1972) Schweiz. Mineral. Petrogr. Mitt. 52, 93–108.Google Scholar