Cupric thiocyanate

Rhodan-ion, n. thiocyanogen ion, CNS -kali, -kalium, n, potassium thiocyanate, -kalzium, n. calcium thiocyanate, -kupfer, n. cupric thiocyanate, copper(II) thiocyanate. -iSsung, /. thiocyanate solution, -metall, n. (metallic) thiocyanate, -methyl, n. methyl thiocyanate, -natrium, n, sodium thiocyanate, -nickel, m. nickel thiocyanate, -quecksilber, n. mercury thiocyanate, -salz, n. thiocyanate, -sdure, /. (Org. Chem.) thiocyan(at)o acid, -tonerde, /. aluminum thiocyanate. 

On addition to boiling water, black cupric thiocyanate converts to the white cuprous salt with violent gas evolution. It is suggested that the gas is hydrogen cyanide, though carbon dioxide seems probable. 

Amino-6-methylbenzothiazole has been prepared by the action of cupric thiocyanate,1, 2 3 or of chloramine and ammonium thiocyanate,4 on -toluidine by the action of chlorine on di- -tolylthiourea 5 or of bromine on acetyldi- -tolylthiourea 6 by treatment of />-tolylthiourea with halogens7 or acid halides. 8 0110,11 12 2-Aminobenzothiazole has been prepared in... 

Cupric thiocyanate, Cu(CNS)2.—The thiocyanate is formed as a velvet-black precipitate by adding basic cupric carbonate or cupric hydroxide to a solution of thiocyanic acid, and by the interaction of potassium thiocyanate and concentrated solutions of cupric salts.8 It is very unstable, being transformed by contact with water into cuprous thiocyanate.9 With ammonium hydroxide it yields blue, aeicular crystals of ammonio-cupric ihiocyanaie, Cu(CNS)2,2NHs, also produced by dissolving cupric hydroxide in ammonium thiocyanate.10... 

Cupric thiocyanate, the use of which may be considered still another modification of this general procedure, shows promise of being very effective. It releases thiocyanogen merely by the dissociation of the cupric to cuprous salt. 

Cupric thiocyanate, prepared in advance, or a paste of copper sulfate and sodium thiocyanate in equivalent proportions is added to a solution of the compound in methanol or acetic acid, and the mixture is warmed to 35-80° until the black cupric thiocyanate has changed completely to the white cuprous thiocyanate. The product is isolated by dilution with... 

Thio ano-l-naphthoP (Use of Preformed Cupric Thior anate). The cupric thiocyanate is prepared by treating an aqueous solution of copper sulfate with an equivalent amount of aqueous sodium thiocyanate. The precipitate is filtered and washed with ethanol and ether. 

A solution of 3.6 g. (0.025 mole) of a-naphthol in 30 cc. of acetic acid is warmed gently with 19 g. (0.105 mole) of cupric thiocyanate until decoloration of the copper salt is complete. The solution is filtered and diluted with water. An oil separates but soon crystallizes. Becrystalli-zation from carbon disulfide yields 3.6 g. (72%) of 4-thiocyano-l-naphthol, m.p. 112°. 

The stabilities of the triammino-cuprous halides are almost identical, and the dissociation pressures of the ammino-cupric halides lie very near together.6 The stabilities of hexammino-copper halides is also almost identical the compounds are very readily decomposed by water, and hence do not seem to be formed in aqueous solution. Ammino-derivatives of cupric carbonate, cupric acetate, cupric oxide, and cuprous cyanide and thiocyanate are known. These have the general characteristics of the ammines already described. 

The reactions of thiocyanogen may roughly be divided into two types (1) Reactions in which the radical combines directly with metals to form the corresponding thiocyanates, and with cuprous thiocyanate to form the cupric salt. (2) Reactions in which a substitution is effected for example, with aniline, dimethylaniline and phenol, the corresponding jj-thiocyano-derivatives and thiocyanie acid are formed.1... 

Both cupric and cuprous thiocyanates may be obtained by precipitation. The former, which forms as a black precipitate when excess of thiocyanate is added to a copper salt, is unstable, and if allowed to remain under water, loses thiocyanic acid and forms the cuprous salt.5 The latter is precipitated as a white powder by the addition of a soluble thiocyanate to a solution of copper sulphate in the presence of sulphurous acid. 

Cuprous thiocyanate, CuCNS.—The thiocyanate is produced by dissolving cuprous oxide or carbonate in thiocyanic acid, and by the interaction of solutions of potassium thiocyanate and a cupric salt in presence of a reducer, such as ferrous sulphate or sulphurous acid.2 It is a white substance, its solubility at 18° C. being 0 23 mg. in 1 litre of water.3 It dissolves in ammonium hydroxide and concentrated hydrochloric acid, and also in concentrated nitric acid with formation of cupric sulphate. It is employed in the preparation of aromatic thiocyanates.4... 

A crystalline variety of cupric sulphide is produced by heating cupric sulphate with ammonium thiocyanate above 180° C.11 The amorphous form can also be rendered crystalline by heating in a sealed tube with ammonium hydrogen sulphide at 150° to 200° C., the product consisting of lustrous, violet, hexagonal leaflets.12... 

Cupric salts in 0-00001 N-concentration can be detected by the formation of a turbidity with a mixture in solution of an alkali-metal thiocyanate and either gallic acid, tannic acid, catechol, or quinol.5... 

There is a great variety of quantitative methods available for the estimation of copper. Gravimetrically it is estimated as cupric oxide, obtained by ignition of the precipitated hydroxide by precipitation as sulphide, and ignition in an atmosphere of hydrogen to cuprous sulphide by precipitation as cuprous thiocyanate, CuCNS, this salt being either weighed directly, or converted into cuprous sulphide and by electrolytic... 

Copper (Cu, at. mass 63.54) occurs in its compounds in the n, and less often in the I, oxidation state. The properties of copper(I) are similar to those of Ag, Au(I), and T1(I). Copper(I) forms sparingly soluble compounds with the halogens. In solution, copper(I) exists only in complexes, e.g., Cu(CN)2", CuCb", and Cu(NH3)2. Cupric hydroxide, Cu(OH)2, begins to precipitate at pH 5 and shows no amphoteric properties. Copper(II) forms ammine, chloride, tartrate, and EDTA complexes. As a result of oxidizing properties of Cu(ll), its cyanide complex is converted into copper(I) cyanide complex, and sparingly-soluble CuSCN is precipitated from Cu(II) thiocyanate. 

Ammonium sulphamate (AMS) Ammonium sulphate Ammonium thiocyanate Calcium cyanamide Cupric sulphate Cupric nitrate Ferrous sulphate... 

Amiprofos 3-Bromochloro-5,5-dimethyl hydantoin Calcium hypochlorite Copper pyrithione Cupric sulfate pentahydrate Dialkyl dimethyl ammonium chloride Dichlone Endothall, mono (N,N-dimethylalkylamine) salt Fentin acetate Hexachloro-1,3-butadiene Hexetidine Methylenebis (thiocyanate) ... 

Sodium perchlorate monohydrate Sodium m-periodate Sodium sulfide Sodium thiocyanate Sodium thioglycolate Stannous chloride anhydrous Sulfur chloride Sulfurous acid Thiodiqlycolic acid Thiourea Thymolphthalein Zinc oxide Zinc sulfate reagent, analytical chemistry Ammonium acetate Copper oxide (ic) Cupric sulfate anhydrous Ferric nitrate nonahydrate Furfural... 

White silver cyanide, thiocyanate, ferro- and yellow ferricyanide are decomposed with production of ignition-resistant silver. All metal ferro- and ferricyanides of the base metals leave a residue of ferric oxide and the particular metal oxide. For instance, the colorless ferrocyanides of zinc, cadmium, magnesium, calcium, barium, strontium, thorium etc. become yellow-brown Prussian blue and Turnbull s blue become dark (Fe304) and, later, brown (FegOg). Cupric ferricyanide (brown) and cupric ferrocyanide (violet-brown) are blackened when ignited because of the formation of cupric oxide. 

Consequently, a suspension of copper sulfide is completely clarified by cyanides. This fact may be used to detect cyanides even in the presence of ferrocyanides, ferricyanides, iodides, bromides, chlorides, and thiocyanates. The test may be made on paper impregnated with cupric sulfide the sensitivity is greater. 

The formation of (II) provides a quite selective spot test for palladium. Gold must be removed prior to the test because it will cause the development of a deep ruby red in the spot plate test and a diffused violet spot on the paper, apparently due to the reduction of the gold ions to the colloidal metal. Interference may also arise from 0s04 , Os+, Ru+, and RuCle ions because they have distinct self-colors. Mercurous ion causes partial interference by the reduction of part of the palladium to the elementary state, but a positive response can still be seen. It is possible to detect I part of palladium in the presence of 200 parts of platinum or 100 parts of rhodium. Less favorable ratios should be avoided because of the color of these salts. No interference is caused by mercuric and iridic chloride, but free ammonia, ammonium ions, stannous, cyanide, thiocyanate, fluoride, oxalate, and tetraborate ions do interfere. Lead, silver, ferrous, ferric, stannic, cobaltous, nickel, cupric, nitrite, sulfate, chloride, and bromide ions do not interfere. 

The number and variety of ion-specific electrodes is rapidly increasing with no end in sight. At the present writing, it is possible to use such electrodes to determine, either by direct or indirect measurement, ionic concentrations of the following species ammonia, bromide, cadmium, calcium, chloride, cupric, cyanide, fluoride, fluoroborate, iodide, lead, nitrate, perchlorate, potassium, sulfide, sodium, sulfur dioxide, and thiocyanate, all by direct measurement, and by titration methods aluminum, boron, chromium, cobalt, magnesium, mercury, nickel, phosphate, silver, sulfate, and zinc. 

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