Oxalate hydrates

Chemical Designations - Synonyms Ammonium Oxalate Hydrate Diammonium Oxalate Oxalic Acid, Diammonium Salt Chemical Formula (NH,)2C204 H20. 

Brecevic, Lj., Skrtic, D. and Garside, J., 1986. Transfomiation of calcium oxalate hydrates. Journal of Crystal Growth, 74, 399-408. 

Ammonium Oxalate Ammonium Oxalate Hydrate Ammonium Pentaborate Ammonium Pentaborate Tetrahydrate Ammonium Pentachlorozincate Ammonium Perchlorate Ammonium Peroxydisulfate Ammonium Persulfate Ammonium Phosphate Ammonium Phosphate, Dibasic Ammonium Rhodanate Ammonium Rhodanide Ammonium Silicofluoride Ammonium Stearate Ammonium Sulfamate Ammonium Sulfate Ammonium Sulfhydrate Solution Ammonium Sulfide Ammonium Sulfide Solution Ammonium Sulfite Ammonium Sulfocyanate Ammonium Sulfocyanide Ammonium Tartrate Ammonium Thiocyanate Ammonium Thiosulfate Ammonium Zinc Chloride Amorphous Phosphorus AMS... 

N1 - PYRROLIDINE, l-(2-(p-C9,5-DIPHENYL-3-FURYL)PHEN0XY)ETHYU-, OXALATE, HYDRATE... 

Figure 5.7 Decomposition of calcium oxalate hydrate (CaC204-H20) in a Setaram TG-DTA [4], A heating rate of 10°C/min and an argon atmosphere were used. Mass spectroscopy (see subsequent discussion) was also used. Three successive steps in the decomposition are shown (1) CaC204-H20 = CaC204 + H20, (2) CaC204 = CaC03 + CO, and (3) CaC03 = CaO + C02. Note that there is a low concentration of C02 measured with mass spectroscopy (MS) associated with the release of CO. The exotherm associated with the oxidation of CaC204 is not present because of the inert atmosphere.

The oxalate hydrates of the alkaline earth metals, e.g. calcium, strontium and barium, are all insoluble. If a calcium salt made acidic with ethanoic acid is treated with sodium oxalate solution, a white precipitate of calcium oxalate... 

Tomazic, B. Nancollas, G.H. The kinetics of dissolution of calcium oxalate hydrates. J. Cryst. Growth 1979, 46, 355-361. 

Streit J,Tran-Ho EC, KonigsbergerE. Solubility of the three calcium oxalate hydrates in sodium chloride solutions and urine-like iiquors. Monatshefte Fur Chemie 2008 129 1225-36. 

The crystallographic transformations which follow water removal firom Group IIA metal oxalate hydrates have been studied in some detail, but structural [131] changes have not always been considered in kinetic investigations of water removal from transition-metal oxalate hydrates. 

The cases listed in Tables 7 and 19 give general support to this idea. We may also draw attention to three cases where failure to make use of crystal symmetry (which would be chemically feasible) is associated with hydrogen bonds that are significantly longer than those in Type A structures sodium bicarbonate (Sect. XV), potassium hydrogen oxalate (XVI B) and sodium hydrogen oxalate hydrate (XVI C). 

The determination of calcium, strontium, and barium ions in the presence of one another has been carried out by thermogravimetry by Erdey et al. (35,36). The ions are precipitated in the form of mixed metal oxalate hydrates... 

The mass-loss curve and its first derivative (see Chapter 2) of a mixture of calcium, strontium, and barium oxalate hydrates are shown in Figure 4.9. 

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