Cobalt blue basic

The earhest modem history of cobalt aluminium oxide ( cobalt blue qq.v.) pigments commences with Leithner in Vienna, who appears to have discovered the basic process of calcining cobalt oxide and alumina (aluminium oxide) in 1775. Brachert (2001) gives Leithner s blue as a synonym for Cobalt blue. It is also sometimes given as Leidner blue this may additionally explain, by corruption, the use of Leyden blue for cobalt blue. 

Clays and metal oxides and salts such as talc, kaolinite, mica, zinc oxide, titanium oxide, iron oxide, hydrated chromium oxide, cobalt blue, ultramarine blue, calcium carbonate, barium sulfate, etc. are widely used as pigments for cosmetics. Since these pigments possess acidic and basic surface properties, and hence catalytic activity, cos-... 

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. 

Cocaine drug testing kits either manufactured for law enforcement purposes or produced by the underground. These testing kits are simply presumptive color tests. The basic color test used for cocaine is cobalt thiocyanate. The cocaine or any of the other substances from the caine family will form a brilliant blue flaky precipitate in the cobalt thiocyanate. This is an indication that the product is cocaine, procaine, tetracaine, etc. In order to determine whether there is actually any cocaine and not all procaine, stannous chloride is added to the precipitate causing all of the caines except cocaine to dissolve. 

Cobalt Oxy-chloride is obtained as a blue precipitate turning red on pouring a hot solution of cobalt chloride into dilute ammonium hydroxide. The formula CoCl2.3Co0.3-5H20, has been attributed to it.1 Another basic salt, CoC.]2.Co(OH)2.5H20, is stated to result as a precipitate by the action of calcium carbonate upon aqueous solutions of cobalt chloride.2... 

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. 

Cobalt Azoimide, Co(N3)2, and a Basic Azoimide, N3-Co.OH, have been obtained in mixture by Curtius3 as a violet powder. Potassium cobalto-azoimide, KN3.Co(N3)2, is obtained as a bright blue crystalline precipitate when concentrated solutions of the two azo-imides are mixed. It explodes at 225° C. The ammonium analogue, NH4N3. Co(N3)2, has also been prepared. 

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). 

Coordination compounds play important roles in nature. Chlorophyll, which is involved in photosynthesis in plants, is a coordination complex of magnesium. Hemoglobin, the oxygen transporter in the human body, is a coordination complex of iron. Vitamin B12, necessary for the prevention and cure of pernicious anemia, is a coordination complex of cobalt. In all three compounds, the metal ion is in an approximately octahedral environment, its coordination number is 6, and bonded to it are the four nitrogen atoms of a planar porphyrin-hke ring. The basic planar ring structure is closely related to that of the extremely stable blue pigment, Cu(II)phthalo-cyanine. 

As with most complexation and drug solubility situations, pH b a critical variable. Cocaine base b not soluble in water, and if the drug b in thb form rather than a soluble salt, no reaction occurs. Acid b needed to ensure that the cocaine b in the water-soluble ionic form to allow for the formation of a complex. The color b the result of an ion-pair compound formed from the cationic cocaine and the anionic cobalt complex. As with all amine bases, such as ammonia, the base becomes protonated in acidic solution. The pKg of the base determines the ratio of the protonated, ionized form to the neutral form. It is possible to add too much HQ, because cobalt forms a water-soluble pink complex with chloride [CoCy . The pH can also influence the type of complex and ion pair formed. Under acidic conditions, the ion pair favored b [Co(cocaine)2l(SCN)2 (which b pinkbh and soluble in water), while in the neutral-to-basic ranges, the ion pair b assigned the structure [cocaine-H ]2 [Co(SCN)4] (which b a blue solid and soluble in chloroform). The important points of the cobalt thiocyanate reaction with cocaine are summarized in Figures 7.24r-7.26. 

Copper salts form copper hydroxide and basic copper acetate, which can hide the benzidine blue. When small amounts of manganese are to be detected in the presence of large amounts of copper, the test should be carried out as in the presence of cobalt. Cuprous cyanide is formed it should be filtered off before proceeding with the test for manganese. 

Cobalt(ll) varies nicely in color. The hydrated salts and dilute [Co(H20)6] are pink the anhydrous salts and [CoXi] from concentrated weakly basic ligands, tend to be blue. 

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