Cobalt carbonate, basic

The mauve colored cobalt(II) carbonate [7542-09-8] of commerce is a basic material of indeterminate stoichiometry, (CoCO ) ( (0 )2) H20, that contains 45—47% cobalt. It is prepared by adding a hot solution of cobalt salts to a hot sodium carbonate or sodium bicarbonate solution. Precipitation from cold solutions gives a light blue unstable product. Dissolution of cobalt metal in ammonium carbonate solution followed by thermal decomposition of the solution gives a relatively dense carbonate. Basic cobalt carbonate is virtually insoluble in water, but dissolves in acids and ammonia solutions. It is used in the preparation of pigments and as a starting material in the preparation of cobalt compounds. 

Formula Co5(OH)6(C03)2 or 2CoC03 3Co(OH)2 H20 MW 516.73 Synonyms cobalt carbonate hydroxide cobaltous carbonate basic basic cobalt carbonate... 

Cobalt Tetra-carbonyl, Co(C0)4 or Co2(CO)g.—This compound may be prepared by passing carbon monoxide at a pressure of 40 atmospheres over reduced cobalt at 150° C. The higher the pressure the more rapid is the formation of the earbonyl.7 It forms as fine, orange-coloured transparent crystals, which are best preserved by hermetically sealing them in a glass tube in an atmosphere of hydrogen or of carbon monoxide. Upon exposure to air decomposition takes place resulting in the formation of a basic cobalt carbonate. With bromine it yields cobalt bromide and carbon monoxide ... 

Basic Cobaltous Carbonates.—Several of these have been described, although it may well be that many of them are not really separate chemical entities. The three following substances were described by early workers.5... 

Ardizzone. S.. Spinolo, G., and Trasatti, S., The point of zero charge of CO3O4 prepared by thermal decomposition of basic cobalt carbonate, Electrochim. Acta, 40, 2683, 1995. 

The cobalt carbonate basic salt is the commercially-used cobalt carbonate. It is used primarily for manufacturing cobalt pigments. It also is used to prepare cobalt(II) oxide and other cobalt salts. 

Cobalt Triazide (formerly call Cobalt Tri-nitride or Cobalt Azoimide) Co(N,)j, raw 142.99, N58.78% red-brn crysts (anhyd), mp det 148° (0.02 g in 5 sec) (Ref 5), hygroscopic and easily hydrolyzed (Ref 4). The basic cobalt azide, Co(OH)N, was first prepd in 1898 by Curtius Rissom (Ref 1). An aq soln of cobalt azide was studied by Dennis Isham (Ref 2). The anhyd salt, prepd by ihe action of cobaitous carbonate on hydrazoic acid, was prepd by Wohler (Ref 3) and by Wohler Si Martin MptKrvrl C nf nr hrt... 

Lead is immune to distilled water free from C02 and oxygen. Air free from C02 in distilled water corrodes lead. In presence of C02 a film of basic lead carbonate in formed, which prevents further attack. The successful use of lead pipe coils for steam boiler applications depends on the use of pure water condensate, which is free from oxygen and carbon dioxide. In the event of the presence of oxygen, oxygen scavengers such as hydrazine or sodium sulfite together with cobalt nitrate may be used. 

Basic Cobalt Sulphates.—Several of these have been described as resulting on addition of ammonia,4 cobalt carbonate5 or calcium carbonate 6 to solutions of cobalt sulphate under varying conditions. The products obtained consist of blue, bluish green, and lilac precipitates of variable composition. 

Thenard A process for making white lead pigment (basic lead carbonate) by boiling litharge (lead monoxide) with lead acetate solution and passing carbon dioxide gas into the suspension. L.J. Thenard (1777 to 1857) was an eminent French chemist, more famous for his invention of Thenard s blue (cobalt aluminate). 

Properties Red crystals. D 4.13, mp (decomposes). Insoluble in water and ammonia soluble in acids. The cobalt carbonate of commerce is usually the basic salt (see following entry). 

The other type of radical chemistry of importance in the carbohydrate field is one-electron reductions. A handful of these reactions (such as the metallic Zn reduction of acetobromoglucose to triacetylglucal) have been used in synthesis for decades, but, starting with the Barton-McCombie deoxygenation of sugars in the mid-1970s there has been an explosion of interest, as increasingly sophisticated cascades of elementary radical steps have been devised. Such reactions are driven by the homolysis of weak bonds such as Sn-H or N-O under conditions of photolysis or mild thermolysis. Nature uses a similar basic principle in Type II ribonucleotide reductases, where the weak bond in question is the cobalt-carbon a bond in the corrin cofactor. ... 

It was made by dissolving finely ground cobalt carbonate in ethereal hydrazoic acid. After 3-4 days the clear solution is evaporated to obtain reddish-brown crystals. The product, which retains some water tenaciously, is best stored protected from light under ethereal hydrazoic acid [156]. In another approach, cobalt carbonate was dissolved in aqueous hydrazoic acid and the solution concentrated to obtain a basic azide. This was again dissolved in strong hydrazoic acid to produce the reddish-brown crystals. The product was considered to be Co(N3)2 [157] but was not analyzed. 

Orange crystals, m.p. Sl C. Insoluble in H3O soluble in ethanol, ether and other organic solvents. Decomposes in air to the violet, basic Co carbonate. Melting of Co(CO)4 results in a very slow decomposition to cobalt tricarbonyl [Co(CO).3]4 this reaction is clearly observable at 53 °C and proceeds so fast at 60°C that it is complete after two days. After recrystallization from benzene, the tricarbonyl, formed according to the equation Co(CO)4 = Co(CO)3 + CO, consists of deep black crystals. 

Cobalt carbonate Cobalt carbonate (1 1) Cobalt (2+) carbonate. See Cobalt carbonate (ous) Cobalt carbonate, cobalt dihydroxide (2 3). See Cobalt carbonate hydroxide Cobalt carbonate hydroxide CAS 12602-23-2 EINECS/ELINCS 235-714-3 Synonyms Cobalt, bis (carbonato(2-)) hexahydroxypenta- Cobalt carbonate, cobalt dihydroxide (2 3) Cobalt hydroxide carbonate Cobaltous carbonate basic Cobaltous hydroxide carbonate Empirical C2H6C05O12 Formula CoC03[Co(OH)2]n Properties M.w. 516.73... 

Cobaltous carbonate basic. See Cobalt carbonate hydroxide Cobaltous chloride Cobaltous chloride... 

The accepted mechanism for the carbonylation of epoxides is shown in Scheme 17.26, and the basic steps of this cycle are also thought to occur during the carbonylation of aziridines. Alper first proposed a catalytic cycle for the expansion carbonylation of aziridines by [Co(CO)J, and Coates has proposed a similar cycle for epoxide carbonylation catalyzed by complexes containing both Lewis acids and cobalt-carbonyl anions (Scheme 17.26). This mechanism consists of four steps (1) the activation of substrate by coordination to a Lewis acid (2) the S 2 attack on the substrate by [Co(CO)J (3) the insertion of CO into the new cobalt-carbon bond, and the subsequent uptake of CO and (4) ring closing with extrusion of product and regeneration of the catalytic species. 

More interesting is the finding by R. H. Abeles of Brandeis University that the C-5 hydrogen of the coenzyme is also replaced by tritium when 1,2-[1- H] propanediol is used as substrate and the tritium could be transferred back to the product. In his view, the three nonequivalent hydrogen atoms of the 5 -deoxyadenosine moiety have equally a one-third probability of transfer back to the substrate. Consequently, the enzyme does not distinguish between the two prochiral hydrogens at C-5 and shows that the role of the coenzyme Bi2 is basically to act as carrier. This apparent lack of stereoselectivity involved an homolytic cleavage of a cobalt-carbon bond (see below). 

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