CALCIUM THIOSULFATE

Product Name
CALCIUM THIOSULFATE
Chemical Name
CALCIUM THIOSULFATE
Synonyms
CALCIUM THIOSULFATE
CBNumber
CB6768322
Molecular Formula
CaO3S2
Formula Weight
152.21
MOL File
Mol file
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Hazard and Precautionary Statements (GHS)

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CALCIUM THIOSULFATE Chemical Properties,Usage,Production

Description

Calcium thiosulfate has the molecular formula of CaS2O3 and the molecular weight of 152.2082 g/mol. It can be prepared by the reaction of sodium thiosulfate upon the chloride:
CaCl2=Na2S2O3 ? CaS2O3+2NaCl
Since calcium thiosulfate is soluble in water (50.2 g/100 ml at 20°C), the solution must be evaporated at a low temperature to crystallize the product (salt-out temperature ~15°F (-9.4°C). A hexahydrate, CaS2O3·6H2O, is the result. Its CAS number is 10124- 43-3 while that of the anhydrate is 10124-41-1. Its density is 1.87 g/cm3 and it loses four waters of hydration at 45°C and the other two at about 85°C. Further heating to 112°C causes it to decompose, forming S, SO2 and calcium sulfate:
2CaS2O3+heat ? 2CaSO4+S+SO2
Thiosulfuric acid could also be used to prepare this salt at an acidic pH. The expected result is the hexahydrate. However, there is no report of an investigation concerning the product(s) formed as a function of pH of precipitation. A high-purity calcium thiosulfate can be prepared by a metathesis reaction of ammonium thiosulfate and calcium hydroxide or calcium oxide. Aqueous solutions of high-purity calcium thiosulfate, in concentrations up to about 30% by weight, are prepared by removing substantially all of the co-product ammonia under conditions that minimize the decomposition of the thiosulfate ion. Heating the reaction mixture to a temperature of about the boiling point at atmospheric pressure is used to prepare aqueous solution of about 10% by weight calcium thiosulfate, and lower reaction temperatures are employed to prepare more concentrated aqueous solutions of calcium thiosulfate up to about 30% by weight, which is the saturation point.
Calcium thiosulfate is supplied as a solution commercially. The clear solution has little odor, and the pH is in the range of 6.5–7.5. It is used in dechlorination, ozone and hydrogen peroxide quenching, concrete and cement formulations, photographic processes, coatings, stabilizers, and reactant for precious and nonprecious metals. It is also used as a “liquid lime” in agriculture. Calcium thiosulfate is a reducing agent. It is routinely used as a titrant to determine concentrations of oxidants such as hypochlorite in bleach and dissolved oxygen in water. It instantly dechlorinates water, and is used to stop a bleaching action in the paper making industry.

CALCIUM THIOSULFATE Preparation Products And Raw materials

Raw materials

Preparation Products

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CALCIUM THIOSULFATE Suppliers

MP Biomedicals, Inc.
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Country
United States
ProdList
6561
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81
City Chemicals Corporation
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Country
United States
ProdList
6460
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72