Free Energy of Formation of Beidellite from Apparent Solubility Measurements*

U. K. Misra and W. J. Upchurch
Department of Agronomy, University of Missouri, Columbia, MO 65201, U.S.A.
* Contribution from the Missouri Agr. Exp. Sta., Journal Series Number 7087.
Research Associate and Associate Professor of Agronomy, respectively.

Abstract: The structural formula for K and Mg saturated beidellite was calculated from the total elemental analysis of the <0.2 µ clay fraction of the B2t horizon of a Mexico soil. The free energies of formation (ΔGf°) of K-beidellite and Mg-beidellite as determined from their apparent solubilities were −2491.3 and −2484.0 ± 3.2 kcal per mole, respectively. The free energies of formation correspond to a clay mineral structure calculated on the basis of a 24 oxygen cell.

Clays and Clay Minerals; December 1976 v. 24; no. 6; p. 327-331; DOI: 10.1346/CCMN.1976.0240609
© 1976, The Clay Minerals Society
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