Gibbs free energies of formation of uranyl silicates at 298.15 K

New estimates of the Gibbs free energies of formation at 298.15 K of uranyl silicates (uranophane, boltwoodite, sodium boltwoodite, kasolite, sklodowskite, cuprosklodowskite, weeksite, haiweeite, soddyite, synthetic sodium boltwoodite, and synthetic sodium weeksite) using the methodologies of Chermak & Rimstidt (1989, 1990) and Chen (1975) are reported. These results are compared to earlier estimates by Langmuir (1978), Hemingway (1982), Finch (1997) and Chen et al. (1999) as well as estimates based on experimental solubilities measured by Nguyen et al. (1992).