Cobalt sesquioxide

Synonyms cobaltic oxide cobalt trioxide dicobalt trioxide cobalt sesquioxide... 

According to T. Curtius, feme chloride is reduced by hydrazine to ferrous chloride a reaction investigated by E. Miiller and G. Wegdin, and F. Schrader. E. J. Cuy found that in the reaction between hydrazine and a ferric salt in acid soln., one mol of hydrazine requires between one and two eq. of ferric salt for oxidation. The limiting reaction may be expressed as follows N2H 5-)-Fe" =NH 4+JN2+H +Fe". A. W. Browne and F. F. Shetterly showed that ferric oxide and hydrazine in aq. soln, yield ammonia, but no hydrazoic acid, while nickel sesquioxide and cobalt sesquioxide yield ammonia and traces of hydrazoic acid. H. Franzen and 0. von Mayer made complex cobalt salts—e.g. CoC12(N2H4)2, etc.—with hydrazine in place of ammonia. T. Curtius found that platinum is precipitated when a soln. of hydrazine is added to a neutral soln. of platinum... 

Cobalt Sesquioxide, Co203, results when cobalt nitrate is gently heated to 180° C.4 It is a black, amorphous powder, of density 518. Hydrogen begins to reduce it at 182° C.5 It may be regarded as the cobalt salt of cobaltous acid, namely, cobaltous cobaltile, CoCo03. 

SYNS C.I. 77323 COBALTIC OXIDE COBALT OXIDE (8CI,9CI) COBALT(3+) OXIDE COBALT PEROXIDE COBALT SESQIOXIDE COBALT SESQUIOXIDE COBALT TRIOXIDE DICOBALT OXIDE DICOBALT TRIOXIDE... 

C.l. 77323 Cobalt black Cobalt oxide Cobalt oxide (C02O3) Cobalt peroxide Cobalt sesqioxide Cobalt sesquioxide Cobalt trioxide Cobalt(3+) oxide Cobalt(lll) oxide Cobaitic oxide Dicobalt oxide Dicobalt trioxide EINECS 215-156-7. A pigment used in coloring enamels and glazing pottery. Black solid insoluble In H2O. soluble in H2SO4. Atomergic Chemetals Cerac Noah Chem. 

How do the monoxides of chromium, manganese, iron, cobalt, and nickel compare in basic strength with the oxides of copper and zinc and with the oxides of the alkali and alkaline earth metals How do the sesquioxides, R203, compare with the monoxides of this group as regards basic strength ... 

Cobalt monoxide is a well-defined chemical entity, but the existence ol monoxides of rhodium and iridium has not as yet been satisfactorily demonstrated. All three metals yield sesquioxides, of the type R203, and dioxides, of the type R02. The last named exhibit weak acidic tendencies in that they can unite with bases to form cobaltites, rhodites, and iridites respectively, analogous to the ferrites, ruthenites, and osmites mentioned in the previous section, and exhibiting an interesting relationship to the chromites and manganites. 

The sesquioxide, Cr Oa, containing trivalent chromium, is an amphoteric oxide. It yields chromic salts, such as chromic chloride, CrCla, and sulphate, Cr2(S04)a, which are very stable and show great similarity to the ferric salts and to salts of aluminium as, for example, in the formation of alums. Since, however, chromic oxide functions as a weaker base than chromous oxide, the latter having a lower oxygen content, the chromic salts are more liable to hydrolysis than the chromous salts. This is well marked in the case of the chlorides. Again, in spite of the stability of chromic salts, only a slight tendency to form simple Cr " ions is exhibited, whilst complex ions are formed much more readily, not only complex anions, as in the case of iron and aluminium, but also complex cations, as in the extensive chromammine series. In this respect chromium resembles cobalt and platinum. 

Methylene groups in the a positions with respect to carboxylic groups are changed to carbonyl groups thus oi-keto esters are formed. Methyl phenylacetate is oxidized with air in the presence of cobalt benzoate at 110-115 °C to methyl phenylglyoxylate in 86% yield [8], Diethyl malonate is converted by nitrogen sesquioxide (N2O3) into diethyl mesoxalate in 74-76% yield [450],... 

Powder XRD analysis of the reduced LnCoO, perovskites showed only the presence of the sesquioxides La,0, (hex), Nd.O, (hex), Sm,0, (cub) and Gd,0, (cub). The apparent absence of reflections for the metallic cobalt indicates a high metallic dispersion with Co" particles smaller... 

XRD analyses of the used catalysts Gd-Co-O and Sm-Co-O showed similar patterns to the reduced catalysts with very strong and sharp peaks for the sesquioxides Gd,0, and Sm20,. On the other hand, the XRD analysis of the La-Co-O catalyst after reaction at 1023 K for 19 h clearly showed the formation of the perovskite LaCoO,. Therefore, it is not surprising that the only reaction products observed were water and carbon dioxide. This agrees with previous works on this perovskite and other forms of cobalt oxide which have been shown to be active catalysts for methane combustion and also for CO and H, oxidation [19], The high Co/Ln surface ratio determined by XPS for the used catalyst is expected for a perovskite like surface. 

This work suggests that the high activity and selectivity of the catalysts Gd-Co-O and Sm-Co-O for the partial oxidation of methane to synthesis gas is due to the stability of the cobalt in its reduced state over the sesquioxides Gd,0, and Sm,0,. In the case of La-Co-O and Nd-Co-O reoxidation of cobalt to the original perovskite structure causes loss of activity and selectivity. TPO experiments with reduced Ln-Co-0 (Ln = La, Nd, Sm and Gd) catalysts indicated that reoxidation takes place in two steps first oxidation of the supported Co to the spinel Co,04 (Co- Co, 04) and further the oxidation of the Co-" to Co with a simultaneous solid state reaction with Ln,0, regenerating the perovskite structure. It was observed that the temperature for the second oxidation step is strongly dependent on the nature of the lanthanide increasing in... 

As a result of the diminution in the range of oxidation states which has already been mentioned, the number of oxides formed by these elements is less than in the preceding groups, being confined to two each for cobalt (CoO, C03O4) and rhodium (RhiOB, RhOi) and to just one for iridium (IrOi) (though an impure sesquioxide IriOs has been reported — see below). No trioxides are known. 

But the admirable researches of Gay-Lussac and of Mitscherlich have established the fact, that in many instances, different compounds assume the same form. Thus, the following substances, and many others, take the form of the cube, tetrahedron, or regular octohedron, which are geometrically connected. Chloride of sodium (sea-salt), chloride of potassium, sal ammoniac bromide of potassium iodide of potassium sulphuret of lead fluoride of calcium bisnlphuret of iron arseniuret of cobalt sulphate of alumina and potash (alum) ammonia alum chrome alum, iron alum sesqnioxide of iron, sesquioxide of aluminum, sesquioxide of chromium. In like manner, other crystalline forms are found to be common to many different compounds, although none occurs so frequently as the cube and its congeners. 

Stn. Sesquioxide of Cobalt.— When bleaching liquor (hypochlorite of lime) is added to solutions of protoxide of cobalt, or when chlorine is passed through hydrated protoxide suspended in water, a black powder is formed, which is hydrated peroxide. 3 eq. protoxide, and 1 eq. chlorinej yield 1 eq. protochloride and 1 eq. peroxide. 3 CoO -f- Cl = Co, 0, -J- CoCl. 

Syn. SesqniouAde of Nickel.—May be formed by passing chlorine through water in which the hydrated protoxide is suspended. It is an indifferent oxide or superoxide, analogous to sesquioxide of cobalt. It is a black powder. 

Salter (1869) discusses a pigment which he calls cobalt Prussian blue, although he reports that it was not in ordinary use. It appears to be essentially Prussian blue (q.v.) with the iron(III) replaced by cobalt (Fe replaced by Co " ), prepared by mixing yellow prussiate of potash. .. with a solution of oxalate of sesquioxide of cobalt . Salter further noted that it was described by Gmelin, but reported the product is. .. a dingy slate colour . 

---