Cobalt selenates

Klein [40KLE] measured the solubility of cobalt selenate in water as a function of temperature and presented the results in a table and a graph. Several hydrates are formed and the transition temperatures observed were heptahydrate hexahydrate 284.6 K, hexahydrate tetrahydrate 306.7 K, and tefrahydrate — monohydrate 346.7 K. CoSe04 6H20 readily forms metastable saturated solutions up to about 340 K. 

This figure is also obtained by interpolation from the measurements by Klein. 

The value of solubility product of CoSe04-6H20(cr) at 298.15 K, CoSe04-6H20(cr) Co + SeO 6H20(1) 

Batyreva [90KUM/BAT] to be - 1.54, see Appendix A. The results are based on the same isopiestic data by Ojkova and Staneva [890JK/STA]. The former value  

The standard Gibbs energy of formation of CoSe04-6H20(cr) is calculated from the Gibbs energy of Reaction (V.132) and the values of AfG° for the ions and water to be  

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Cobaltous Selenate, CoSe04.6H20, is known.6 When a neutral solution of this salt is heated in a sealed tube to 250° C., an insoluble basic salt is obtained in the form of small red needles, to which the formula 4Co0.3Se03.IT20 has been given.6... 

Cobaltic Selenate, Co SeO g.lSHjP, is an unstable salt obtained by electrolysis of cobaltous selenate at — 10° C.7... 

JK/ST0] Ojkova, T., Stoilova, D., Staneva, D., Thermodynamical study on the zinc selenate-cobalt selenate-water system at 25°C, Monatsh. Ghent., 125, (1994), 1067-1074. Cited on pages 264, 321. 

Barkov, D., Christov, C., Ojkova, T., Thermodynamic study of aqueous rubidium and cobalt selenate system at the temperature 298.15 K, J. Chem. Thermodyn., 35, (2003), 689-697. Cited on pages 321,427,428,585. 

Several reports were published on the PT/metal hybrids or PT/inorganic nanocomposites. Novel bithiophene with a pendant fullerene substituent was synthesized by electrochemical polymerization [350]. It was revealed that a photoinduced electron was transferred from the donor cable (PT) to the pendant acceptor cable (fullerene moieties). On the other side, it was demonstrated that a highly conducting cobalt selen-PT hybrid material catalyzed... 

A current area of interest is the use of AB cements as devices for the controlled release of biologically active species (Allen et al, 1984). AB cements can be formulated to be degradable and to release bioactive elements when placed in appropriate environments. These elements can be incorporated into the cement matrix as either the cation or the anion cement former. Special copper/cobalt phosphates/selenates have been prepared which, when placed as boluses in the rumens of cattle and sheep, have the ability to decompose and release the essential trace elements copper, cobalt and selenium in a sustained fashion over many months (Chapter 6). Although practical examples are confined to phosphate cements, others are known which are based on a variety of anions polyacrylate (Chapter 5), oxychlorides and oxysulphates (Chapter 7) and a variety of organic chelating anions (Chapter 9). The number of cements available for this purpose is very great. 

Other compounds may be found in leachate from landfills, e.g., borate, sulfide, arsenate, selenate, barium, lithium, mercury, and cobalt. In general, however, these components are not often measured when they are measured, they are usually present in very low concentrations and are considered only of secondary importance. 

The bio-availabilities of these elements through the gastrointestinal tract vary markedly. Molybdenum, iodine, fluorine, and arsenic are apparently highly bio-available, whereas medium uptake occurs with haem iron, cobalt, zinc, chromium in the presence of a glucose tolerance factor, selenium, either as selenate or as organo selenium compounds, whereas only low bio-availability is experienced with non-haem iron,... 

Christov calculated the parameters in the Pitzer ion interaction model from isopiestie measurements at 298.15 K by Ojkova and Staneva [890JK/STA]. This reference contains (interpolated) osmotic coefficients of zinc, magnesium, cobalt, and nickel selenate solutions from 0.1 mol-kg to saturated solution. Sodium chloride standards were used and the agreement between duplicate determinations was 0.2% or better. 

Sulfur has an antagonistic effect on several essential trace elements. Excessive amounts of sulfur can induce a secondary deficiency of copper (mainly in animals), cobalt and selenium. Ho vever, not only the sulfur amino acid cysteine but also sulfate eliminates the adverse effects of copper-, cobalt-or selenium-based toxicities (Baker and Czarnecki-Maulden 1987). Sulfate increases the urinary loss of selenate, but not of selenite this explains the assumption that there is a direct antagonism between sulfate and selenate (Schrauzer 1998). 

Potassium cobalt(ll) selenate hexahydrate K3Co(Se03)3 6H3O 28041-86-3 631.14 red monoci cry 2.61 ... 

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