Thio cyanic acid

Nickel Thiocyanate, Ni(CNS)2, has been obtained in the anhydrous condition as a chocolate-coloured amorphous powder. The hydrated salt, 2Ni(SCN)a.3HaO, obtained by dissolving nickel carbonate in thio-cyanic acid is a yellowish brown crystalline powder.10 Double salts... 

In very dilute solution the intensity of colour produced is not quite proportional to the amount of iron present—indeed, the more concentrated solution becomes decolorised on dilution, as also by addition of oxalates, tartrates, etc. The decoloration on dilution is usually explained on the assumption that the water hydrolyses the red undissociated salt into yellow colloidal ferric hydroxide and free thio-cyanic acid —... 

Alkyl Thio-cyanates Alkyl Iso-thio-cyanates.—In the alkyl derivatives of thio-cyanic acid we again have isomerism exactly analogous to that in the unknown cyanates and the known iso-cyanates. 

C. CYANIC ACID, ISO-CYANIC ACID, THIO-CYANIC ACID AND THEIR SALTS... 

While free cyanic acid is not known the thio-cyanic acid is a more or less stable liquid. The salts of thio-cyanic acid are also known, two of them being quite common reagents, viz.. 

Iso-thio-cyanates.—Isomeric with the thio-cyanic acid would be iso-thio-cyanic acid which if analogous in constitution to the iso-cyanic acid should have the constitution H—N = C = S. Neither this compound nor metal salts of it are known but alkyl derivatives are known as constituents of oil of mustard (p. 165). 

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. 

Compounds with C-N bonds form a significant branch of the inorganic chemistry of carbon these comprise hydrogen cyanide (HCN) and the cyanides, cyanic acid (HNCO) and the cyanates, and thio-cyanic acid (HNCS) and the thiocyanates. 

Wohler s synthesis of urea by which a product of the living cell was first prepared artificially more than a century ago is the prototype of many addition reactions which take place with the reactive molecules of cyanic acid and its esters, as well as with the series of analogous thio-compounds. In these reactions NH3 is added to the C = N double bond ... 

The prefix thio- indicates that sulfur is present, usually as a replacement for one or more oxygen atoms in a compound whose name is familiar. For example, in thiosulfuric acid, one 0 atom of sulfuric acid has been replaced by an S atom in thiocyanic acid, the only 0 atom of cyanic acid has been replaced in thioar-senic acid, all of the O atoms of arsenic acid have been replaced by S. The rules of naming do not normally show how many 0 atoms are replaced. HSCN is placed in Table 8-3 because of the many similarities between oxygen and sulfur. 

While the liquid-liquid extraction of inorganic elements as coordination complexes with thiocyanate ions can be traced back to Skey (1867), the extraction from hydrochloric acid into ether of iron(III) (J. W. Rothe, 1892) or gallium (E. H. Swift, 1924) depends on the formation of solvated acido complexes derived from HMC14 extractions of metal complexes from nitric, thio-cyanic, hydrofluoric, hydrochloric and hydrobromic acids were studied exhaustively by Bock and his collaborators (1942—1956).6... 

This same substitution of sulphur for oxygen occurs in the case of cyanic acid and its salts, e.g., potassium thio-cyanate and ammonium thiocyanate used as reagents in testing for ferric iron. 

Corresponding to the cyanic and iso-cyanic acids and their salts and esters, we have the analogous sulphur or thio compounds formed by the replacement of oxygen by sulphur. The relationship of these sulphur compounds to the oxygen compounds is exactly the same as that existing between sulphuric acid and thio-sulphuric acid. 

Sulfocyankalium, n. potassium thiocyanate, sulfocyansauer, a. of or combined with sulfo-cyanic (thiocyanic) acid, sulfocyanate (thio cyanate) of. 

---