Cobalt hydroxide, divalent

Use of metal hydroxides opens some possibilities in the discussed syntheses. Thus, as a result of interaction (3.83) of (5-ketoimines 656 with divalent nickel, copper, and cobalt hydroxides in acetone solution, the p-ketoiminates 657 were obtained [205] ... 

Cobalt can occur in divalent or trivalent forms in oxide and hydroxide structures, and the ionic radii of cobalt species are similar to those of corresponding manganese species. Divalent cobalt hydroxide is much more soluble than divalent lead hydroxide. From data in Table I... 

Table 1 shows the properties of smectite-type materials prepared. Smectite materials prepared at lower pH had fewer sodium ions, higher surface areas, and larger pore volumes for a series of samples containing the same divalent cation species (nickel and cobalt) in the octahedral sheet. The adsorption of methylene blue on all the synthetic smectites shows that the smectite fragments are negatively charged. The Si M ratios of synthetic smectites were about 8 6, indicating that most of divalent cations exist in octahedral layers and small amount of divalent cations would exist as hydroxide or oxide cluster in smectite materials. However, the amounts of the hydroxide or oxide cluster were small, because only smectite structures were observed in XRD patterns and EXAFS Fourier transforms of synthetic smectites calcined at 873 K. 

Ammonia solution precipitation of iron(II) hydroxide occurs (cf. reaction 1). If, however, larger amounts of ammonium ions are present, the dissociation of ammonium hydroxide is suppressed, (cf. Section 1.15), and the concentration of hydroxyl ions is lowered to such an extent that the solubility product of iron(II) hydroxide, Fe(OH)2, is not attained and precipitation does not occur. Similar remarks apply to the other divalent elements of Group III, nickel, cobalt, zinc and manganese and also to magnesium. 

Acetates n. (1) Metallic salts derived from acetic acid by interaction of the metallic oxide, hydroxide, carbonate with the acid, or by the esters derived by interaction of alcohols with acetic acid. Typical metallic salts are lead, cobalt, and manganese acetates. Common esters are ethyl, propyl, isopropyl, butyl, and amyl acetates. Acetate salts have the formula CH3COOMe, where Me is a monovalent metal. Divalent metals hke lead, etc., obviously combine with two acid radicals. The formula given above for the acetate salts apply also to esters, except that the Me becomes an alkyl radical. (2) It is also used colloquially for cellulose acetate plastics. Goldberg DE (2003) Fundamentals of chemistry. McGraw-Hill Science/Engineering/Math, New York. Vincenti R (ed) (1994) Elsevier s textile dictionary, 2003. Elsevier Science and Technology Books, Amsterdam. 

In addition to the exclusion of carbon dioxide, it is necessary to exclude oxygen from reactions where cations of the metal hydroxide layer are easily oxidized under basic conditions. LDHs of this type include manganese, cobalt (131) and iron in the divalent oxidation state, and vanadium in the trivalent state. Reactions involving these metal ions have formed LDHs with, for instance, Co " /Co and Fe " /Fe metal content, with the latter, known as green rust, being discussed earlier in Section II.J. 

Cobalt forms both divalent and trivalent cations. Like iron, it forms oxide/ hydroxide phases in both oxidation states as well as mixed oxidation state phases. Cobalt(II) oxide is used extensively in the ceramics industry to produce blue-coloured glazes. Cobalt(II) hydroxide has two forms, pink and blue, with the former being more stable. It is used as a drying agent or as a catalyst in the manufacture of battery electrodes. 

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