Barium thiocyanate

Barium thiocyanate was first prepared by Berzelius, who roasted barium hexacyanoferrate(II) with sulfur. It has also been obtained by reaction of barium carbonate with a solution of thiocyanic acid, by conversion of ammonium thiocyanate through the copper (I) thiocyanate by consecutive reactions with copper(I) chloride and barium hydroxide, by treatment of Prussian blue with barium sulfide, and by reaction of barium sulfide, sulfur, and cyanamide. The procedure described below makes possible the preparation of barium thiocyanate in any desired quantity from barium hydroxide and ammonium thiocyanate as starting materials. The 3-hydrate, which is obtained first, is dehydrated readily to yield anhydrous barium thiocyanate. 

To the filtrate is added 6 N sulfuric acid until the solution is only faintly alkaline to litmus (just colorless to phenolphthalein) the remainder of the barium hydroxide is neutralized with carbon dioxide. The solution is heated to boiling to remove any barium hydrogen carbonate that may have formed. It is preferable, but not absolutely necessary, to digest the mixture overnight on a steam bath. The solution is filtered through paper precoated as before, the filtrate is heated to boiling, 0.5 g. of activated charcoal is added, and the solution is filtered again. 

The final filtrate is concentrated until the boiling point rises to 125°, but no higher. The solution is allowed to cool to room temperature and is then placed in an ice bath. The crystals of the 3-hydrate that form are collected on a BUchner funnel, f The product is dried in air. Yield, approximately 115 g. (75 per cent). Amd. Calcd. for Ba(SCN)2 SCN, 45.76. Found SCN, 46.04. 

Barium thiocyanate is a white solid that is very soluble in water but has a very steep temperature-solubility gradient. This solid is also soluble in acetone, methanol, ethanol, methylamine and ethylamine, moderately soluble in isopropylamine and dimethylamine, but insoluble in trimethylamine. The anhydrous salt is very hygroscopic. Crystallization from water yields the 3-hydrate as well-formed, needle-shaped crystals. Double salts are formed with the thiocyanates of the alkali and other alkaline earth metals.  

The reaction mixture used in this procedure may find application in freezing mixtures because of its high negative heat of reaction. Barium thiocyanate has been used in the dye and color printing industries and as a dispersing agent for cellulose. It can be converted readily by treatment with a dilute sulfuric acid to give dilute solutions of thio-cyanic acid, or into the thiocyanates of other metals by precipitation of barium sulfate. 

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Probably first obtained by Hantzsch and Arapides (105) by condensation of a,/3-dichlorether with barium thiocyanate, and identified by its pyridine-like odor, thiazole was first prepared in 1889 by G. Popp (104) with a yield of 10% by the reduction in boiling ethanol of thiazol-2-yldiazonium sulfate resulting from the diazotization of 2-aminothiazole. prepared the year before by Traumann (103). The unique cyclization reaction affording directly the thiazole molecule was described in 1914 by Gabriel and Bachstez (106). They applied the method of cyclization, developed by Gabriel (107, 108), to the diethylacetal of 2-formylamino-ethanal and obtained thiazole with a yield of 62% - Thiazole was also formed in the course of a study on the ease of decarboxylation of the three possible monocarboxylic acids derived from it (109). On the other... 

Hydroxy-4-methylthiazole has been prepared in 68% yield through the reaction of barium thiocyanate with chloroacetone (70). 

Baryum, n. barium, -chlorhydrat, n. barium chloride. -hydrat, n. barium hydroxide, -hyperoxyd, n. barium peroxide, barium dioxide. -jodid, n. barium iodide, -lack, m. barium lake, -oxydhydrat, n. barium hydroxide. -platincyaniir, n. barium cyano-platinite, barium cyanoplatinate(II). -rho-danid, n. barium thiocyanate, -salz, n. bar ium salt. 

Rhodan-baryum, n. barium thiocyanate, -eisen, n. iron thiocyanate, esp. ferric thiocyanate, iron(lll) thiocyanate, -eisenrot, n. ferric thiocyanate, iron (III) thiocyanate. 

It is expected, therefore, that the cyclic hexamer also exhibits a characteristic tendency to complex with cations. In fact, the addition of an acetonitrile solution of metal thiocyanates to a solution of the cyclic hexamer in the same solvent shifted the carbonyl absorption to a lower wave number46,52 The shift values depended upon the kind of metal ions present, and the largest shift value of 40 cm-1 was observed for barium thiocyanate (molar ratio of Ba2+/hexamer = 10). In addition to the shift of the carbonyl absorption, the intensities of the C—O-C stretching vibrations around 1200 cm-1 varied appreciably. 

Mixtures of thiocyanates with chlorates (or nitrates) are friction- and heat-sensitive, and explode on rubbing, heating to 400°C, or initiation by spark or flame [1]. A violent explosion occurred when a little chlorate was ground in a mortar contaminated with ammonium thiocyanate. A similar larger-scale explosion involving traces of barium thiocyanate is also described [2],... 

Barium thiocyanate Pieters, 1957, 30 Mixtures may explode See Sodium thiocyanate, below... 

For (203), models indicated that the isomer containing cis-syn-cis hydrogen atoms on the cyclohexane ring should be able to form clam-type complexes, provided the cyclohexane ring is in the flexible or twist conformation. The models suggested that the cavity defined by the ten oxygen donors would be ideal for K+. However, for the potassium and barium thiocyanate complexes, configurations of type (204) do not occur in the solid state. Instead, two molecules of the bis-crown coordinate simultaneously to two alkali metal ions - both these 2 2 complexes have structures of type (205). 

Barium thiocyanate (2 H2O) [2092-17-3] M 289.6. Crystd from water (2.5ml/g) by partial evaporation in a desiccator. 

An aqueous solution of thioeyanic acid may be prepared by the decomposition of either silver or mercuric thiocyanate with hydrogen sulphide, or by decomposing barium thiocyanate with an equivalent quantity of sulphuric acid. It may also be obtained by distilling... 

Double Salts of Vanadous Thiocyanate.—When vanadous sulphate, V2(S04)3, in solution, is treated with barium thiocyanate, a green solution8 is obtained which is believed to contain vanadous thiocyanate, V(SCN)g, but attempts to isolate this compound have not met with success. Its double salts with the alkali thiocyanates have, however, been obtained in well-defined crystals when an alkali thiocyanate is substituted for the barium salt. The following are known —... 

Thiocyanic acid is formed by reaction of barium thiocyanate solution and dilute sulfuric acid, and filtering off barium sulfate, or by the action of hydrogen sulfide on silver thiocyanate, filtering off silver sulfide. 

Barium hexafluorosilicate, preparation of, for decomposition to silicon tetrafluoride, 4 145 Barium paraperiodate (orthoperiodate), Ba3H4(I06)2, 1 171 Barium dezZro-tartrate, for resolution of tris(ethylenediamine)-cobalt(III) ion, 6 184 Barium thiocyanate, 3 24 Benzalazine, in recovery of hydrazine residues, 1 92 Benzoylacetone, beryllium derivative of, 2 19... 

Barium thiocyanate, 118 Base catalysis, 34 in acylations, 47, 48 of chelate formation, 95 of clevage, 128 of cydization, 127 in hydrolysis, 115 Basicity, of 2-aminothiazole, 90 of 2-imino-4-thiazolines, 124 Beckmann rearrangement, of oxime, 16 Benzaldehyde, with alkyl-acetamidothi-azole, 46... 

Grossmann and Hiinseler 6 prepared the tetrahydrate, Co(CNS)2.4H20, by double decomposition of solutions of cobalt sulphate and barium thiocyanate. The solution is at first red, but becomes blue on concentration, and after remaining in vacuo for some time, deposits beautiful... 

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