The Thermodynamic Hydrate Difference Rule (HDR) Applied to Salts of Carbon-Containing Oxyacid Salts and Their Hydrates: Materials at the Inorganic-Organic Interface

Abstract

The thermodynamic hydrate difference rule (HDR) has previously been explored largely within the compass of inorganic solids. In this paper we extend its range by studying its application to carbon-containing oxyacid salts, which may be regarded as borderline hydrate-forming inorganic or organic material. We study in detail standard thermodynamic data as it appears in the National Bureau of Standards (NBS) tabulation for formate, carbonate, acetate, glycolate, and oxalate salt hydrates, finding the HDR to apply equally as well to these materials as it does to salts with solely inorganic parents. We use the resulting constants to predict thermodynamic quantities for some parent salts.