![]() ![]() The anhydrous compound can be purified by sublimation in vacuum. ĭehydration can also be effected with trimethylsilyl chloride: CoCl If the partial pressure of the water vapor is in equilibrium with the solid, as in a confined but not pressurized contained, the decomposition occurs at about 115☌, 145☌, and 195☌, respectively. On slow heating in an open container, so that the water vapor pressure over the solid is practically zero, water evaporates out of each of the solid 6-, 2-, and 1- hydrates, leaving the next lower hydrate, at about 40☌, 89☌, and 125☌, respectively. On rapid heating or in a closed container, each of the 6-, 2-, and 1- hydrates partially melts into a mixture of the next lower hydrate and a saturated solution-at 51.25 ☌, 206 ☌, and 335 ☌, respectively. The anhydrous compound can be prepared by heating the hydrates. The monohydrate and the anhydrous forms can be obtained by cooling solutions only under high pressure, above 206 ☌ and 335 ☌, respectively. Water ice, rather than cobalt chloride, will crystallize from solutions with concentration below 29%. Cooling saturated aqueous solutions yields the dihydrate between 120.2 ☌ and 51.25 ☌, and the hexahydrate below 51.25 ☌. The solid dihydrate and hexahydrate can be obtained by evaporation. Preparation Ĭobalt chloride can be prepared in aqueous solution from cobalt(II) hydroxide or cobalt(II) carbonate and hydrochloric acid: The octahedron is completed by a pair of mutually trans aquo ligands. Each Co center is coordinated to four doubly bridging chloride ligands. The dihydrate, CoCl 2(H 2O) 2, is a coordination polymer. The anhydrous salt is hygroscopic and the hexahydrate is deliquescent. This species dissolves readily in water and alcohol. The crystal unit of the solid hexahydrate CoClĢO contains the neutral molecule trans- CoClĤ and two molecules of water of crystallization. Hydrates Subunit of CoCl 2(H 2O) 2 lattice. Concentrated solutions are red at room temperature but become blue at higher temperatures. Under atmospheric pressure, the mass concentration of a saturated solution of CoClĢ in water is about 54% at the boiling point, 120.2 ☌ 48% at 51.25 ☌ 35% at 25 ☌ 33% at 0 ☌ and 29% at −27.8 ☌. Solutions Ĭobalt chloride is fairly soluble in water. The vapor pressure has been reported as 7.6 mmHg at the melting point. At about 706 ☌ (20 degrees below the melting point), the coordination is believed to change to tetrahedral. Properties Anhydrous Īt room temperature, anhydrous cobalt chloride has the cadmium chloride structure ( CdClĢ) (R 3m) in which the cobalt(II) ions are octahedrally coordinated. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt compounds in the lab. The anhydrous form is a blue crystalline solid the dihydrate is purple and the hexahydrate is pink. ![]() Claims of the formation of tri- and tetrahydrates have not been confirmed. The compound forms several hydrates CoClĢO, for n = 1, 2, 6, and 9. Finally, based on the different observations reported in the literature, we provide a critical review about the scope and limitations of this widely used chemical hypoxia model to be informative to all researchers interested in the field.Ĭhemical hypoxia cobalt chloride hypoxia inducible factor prolyl hydroxylases.Cobalt(II) chloride is an inorganic compound of cobalt and chlorine, with the formula CoClĢ. The different current hypotheses that explain the establishment of hypoxic conditions using CoCl 2 are also described. The regulation of hypoxia inducible factors by oxygen and the role of CoCl 2 are explained to understand the most accepted bases of the CoCl 2 -induced hypoxia model. This review describes the characteristics of the model, as well as the biochemical and molecular bases that support it. This model has several advantages, and currently, there is a substantial amount of scattered information about how this model works. One of the most commonly used models is cobalt chloride-induced chemical hypoxia because it stabilizes hypoxia inducible factors 1α and 2α under normoxic conditions. Several alternative models have been used to mimic hypoxia. Although a decrease in oxygen concentration is the optimal hypoxia model, the problem faced by many researchers is access to a hypoxia chamber or a CO 2 incubator with regulated oxygen levels, which is not possible in many laboratories. The use of hypoxia models in cell culture has allowed the characterization of the hypoxia response at the cellular, biochemical and molecular levels. ![]()
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