Thallium cyanate

The pseudohalides and related compounds have been investigated by a number of workers. Thallium(I) cyanate and thiocyanate are both known, and the latter has been shown to be ionic in the solid state 288 differing values have been reported for the stability constants in the T1/NCS system in aqueous or mixed water/non-aqueous systems, but the overall evidence is that the complexes are extremely weak.289 The ionic selenocyanate has been reported, but the chemistry has not been investigated.1... 

Fig. 1. Simultaneous separation and detection of anions and cations on a latex agglomerate column. Column Dionex HPIC-CS5 cation exchange column (250X2 mm) with precolumn HPIC-CG5 (50 X 4 mm) eluent 0.5 mM copper sulfate, pH 5. 62 flow rate 0.5 ml/min sample volume 20 gl containing 0.1 m M of each ion detection two potentiomet-ric detectors equipped with different ion-selective electrodes in series. Peaks (1) chloroacetate, (2) chloride, (3) nitrite, (4) benzoate, (5) cyanate, (6) bromide, (7) nitrate, (8) sodium, (9) ammonium, (10) potassium, (11) rubidium, (12) cesium, (13) thallium. Reprinted with permission from [10].

As already remarked, carbon monoxide has a similar reducing action on the oxides of the more easily reducible elements. The product in this case is the dioxide, C02, for example, Fe203+3C0 = 2Fe + 3C02- This action requires a red heat. Another reducing agent, applied by fusing the oxide with it, is potassium cyanide, KCN it is converted into the cyanate, KCNO. The metal thallium may be prepared by its help, T120 + KCN = 2TI + KCNO. As the cyanide is somewhat expensive, it is used only in special cases. 

Thallium(I) forms salts with cyanide (CN ), cyanamide (NCN ), azide (Ns"), cyanate (OCN ), isocyanate (CNO"), thiocyanate (SCN"), and selenocyanate (SeCN ) however, complexes with these hgands, hke the Tl -halide complexes, are very weak. In contrast, the neutral Tl Xs species are not well known, although the Tl -pseudohahde complexes are more or less stable. 

Complex supramolecular architectures have been established for dimethyl-thallium(III) derivatives of polyfunctional nitrogen ligands, e.g. the cyanide, the azide, the cyanate, the thiocyanate [177], the dicyanamide, and the tricyanomethide [178], The cyanide, Me2TlCN, 53, contains layers of nearly coplanar CN groups... 

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