Perthiocarbonates

Persulfo-cyansaure, /. perthiocyanic acid, per-sulfocyanic acid, -molybditnsaure, /. per-thiomolybdic acid, tbiopermolybdic acid, -zyansaure, /. perthiocyanic acid. Perthiokoblensaure, /. perthiocarbonic acid, penianisch, a. Peru, Peruvian. 

It was generally supposed that the removal of carbon disulphide from crude coal gas when purified by lime was due to its absorption by calcium sulphide with the formation of calcium thiocarbonate, but Yeoman2 suggests that it is the perthiocarbonate, CaCS4, which is formed. This suggestion accounts for the necessity of the presence of some oxygen in order that absorption may take place. 

Perthiocarbonic Acid, H2CS4.—This acid has not been obtained in a perfectly pure condition, but a dark brown liquid consisting largely of perthiocarbonic acid is obtained when the ammonium salt is treated with 98 per cent, formic acid.1 The liquid is rapidly decomposed by acetone (cf. p. 266), the action being accompanied by crackling, the colour disappearing and sulphur being deposited ... 

Sodium perthiocarbonate, Na2CS4, is formed when an alcoholic solution of sodium sulphide is converted into the disulphide by the addition of sulphur and subsequently treated with carbon disulphide.2 Perthiocarbonates may also be formed by the direct combination of thiocarbonates with sulphur.3 There is no analogy to this latter method of preparation in the case of percarbonates this fact is usually regarded as illustrating the superior chain-forming power of sulphur atoms as compared with oxygen atoms. 

Potassium perthiocarbonate, K2CS4, and its adducts K2CS4,nL (L = MeOH or Mc2NH, n = 1 L = H20, n = 0.5) have been prepared and characterized by t.g.a., tensiometry, X-ray diffraction, and i.r. spectroscopy. The adducts have the characteristics of inclusion compounds in which the geometry and arrangement of the CS - ions in the crystal allow the inclusion of MeOH but not the larger PrOH molecules. 

Addition of CS2 to DMF solutions of [Ph4P] 2 [8=1 0(17 -84)2] and [Ph4P]2[(84)Mo284)(82)] results in the formation of perthiocarbonate derivative complexes (160) (Fig. 23 Table XIII). The illustrated pathways are based on C82 addition mechanisms involving the Mo-i7 -82 units. It should be noted that addition to the Mo=8 unit, followed by intramolecular 8 transfer, also is a possible pathway to (084) . Both cis and trans isomers of the [8=Mo( 17 -084)2] anion have been isolated (161). The [0=Mo (S4)2] complex is unreactive toward C82 unless activated by PhgP (73b). 

The structures of various (084) and ( 83) complexes have been determined (Tables I and III). The vibrational infrared, NMR, and electronic spectra of the Mo-trithio- and perthiocarbonate complexes have been compiled in Table XIII. The energy of the C=8 vibration of the coordinated ( 83) " ligands invariably is lower ( 980 cm ) than that of the C=8 vibration in the ( 84) complexes ( 1050 cm ) and can be used as a spectroscopic diagnostic criterion for the identification of the ligands with considerable confidence. An additional diagnostic indicator for the ( 83) and ( 84) ligands is the... 

C10H20CIN, Geranylamine hydrochloride, 10, 218 Ci H2oN2r N,N -Di-t-butyl-1,2-ethanediimine (gas-ed), 42B, 1024 C,0H2 N2O2, N,N -Diacetylhexamethylenediamine, 19, 513 Cl H24N2O18, Ethylenediamine ditartrate dihydrate, 43B, 43 Ci H28N2Se 0.5 CS2, Tetramethylammonium perthiocarbonate carbon disulfide solvate, 41B, 37... 

---