Thiocyanate ion, and

LEED has also been used to study the adsorption of halide ions, cyanide and thiocyanate ions, and organic molecules on single-crystal metal surfaces. 

In this investigation, you will examine the homogeneous equilibrium between iron(III) (ferric) ions, thiocyanate ions, and ferrithiocyanate ions, FelSCN) ". ... 

This is the optical density plotted against the time for an experiment in which we took the nitratopentamminecobalt complex in the presence of 0.50M thiocyanate ion since the competition ratio for thiocyanate ion and for water had been determined by Haim and Taube. Knowing the optical densities of all the possible reactants and products, we could calculate what the optical density should be as a function of time according to the mechanism of Haim and Taube. This calculation depends upon a rate constant for the aquation of the nitrato complex which we took from the literature. But one should get a continuously increasing optical density because the thiocyanate complex has a higher optical density than anything else. 

Figure 5. An experiment illustrating the change in stoichiometry in the presence of thiocyanate ion and O represent measurements at 380 and 278 mu, respectively the dotted line represents our evaluation of the initial slope.

Dr. Pearson presented data on the optical density observed when the nitrato-cobaltic complex reacts with thiocyanate ion, and there is nothing to object to in these results. But I think one might be concerned about the theoretical curve calculated using the competition ratio in a table wrhich Haim and Taube presented in the journal. 

One test for the presence of iron ions in solution is to add a solution of potassium thiocyanate, KNCS, and obtain a blood-red coloration due to a - compound of iron and the thiocyanate ion. Write three Lewis structures with different atomic arrangements for the thiocyanate ion and suggest J which one is likely to be the most plausible structure. 

At the same time, it is necessary to take into account that the approach described has a number of exceptions, related for example to the nature of other ligands forming pseudohalide complexes. A series of classic examples of inversion of the bond M — N —> M — S —> M — N have been reported [6,8,11,42-44,59] and are presented in Sec. 2.2.3.5. In this respect, we especially emphasize the capacity of other ligands for soft or hard metals, related with symbiotic [60] and anti-symbiotic [61] effects. Thus, Pearson [61] emphasized that soft ligands, which are placed in a trans position to SCN ion, contribute to N-binding of thiocyanate ions, and hard bases contribute to S-coordination of these ambidentate ligands. Metal oxidation number (Table 1.4) is important in this problem and it regulates soft hard properties of complex-formers. 

Figure 4. Schematic representation of the medium effect on the reaction of methyl iodide with (a) thiocyanate ion and (b) p-nitrophenoxide ion.

An important area of inorganic carbon chemistry is that of compounds with C—N bonds. The most important species are the cyanide, cyanate, and thiocyanate ions and their derivatives. We can regard many of these compounds as being pseudohalogens or pseudohalides, but the analogies, although reasonably apt for cyanogen, (CN)2, are not especially valid in other cases. 

Thiocyanate complexes are formed by molybdenum in the III, IV, and V oxidation states, the last being of the oxo type, for example, [MoO(NCS)5]2. The [Mo(NCS)6]3 ion has been shown conclusively to have N-bonded thiocyanate ions, and this appears likely to be the case also in all other molybdenum thiocyanato species. 

Direct interference from the bromate-HCl reaction should be too slow to be significant. Although extensive formation of a complex e.g. Br02SCN) followed by rate-determining reaction with thiocyanate ion and an alternative (chloride ) path, viz. 

However, more complex sulfur nucleophiles, such as thiourea, thiocyanate ion, and xanthate salts appeared to accomplish deoxygenation of the oxaziridines by ring-opening attack at carbon followed by the usual reactions leading to thia-ziridines, which lost elemental sulfur." ... 

Cyclic carbonates of 1,3-propanediols yield thietanes when treated with thiocyanate ion and heated until carbon dioxide is evolved. Yields vary from 3 to 63%, the yield being greater for 3,3-disubstituted thietanes, as illustrated in the synthesis of the spirothietane, 44. Oxetanes are formed as byproducts in... 

The photocross I inking is completely quenched by 0.005 M thiocyanate ion, and subsequent addition of 0.5 M H2O causes the formation of postcross Iinked polymer containing an unexplained IR absorption band in the carbonyl region. 

The remarkable similarity between the sodium chloride concentration at which the mobility obtained a reasonable value and that at which a first black film was formed suggests that at this concentration chloride ions adsorb to the sulfoxide groups and thus produce a potential which can provide electrostatic repulsion between the monolayers in the soap film. In the case of potassium thiocyanate, adsorption appears to commence at a lower salt concentration, suggesting a stronger free energy of adsorption for the thiocyanate ion and consequently a greater extent of adsorption. Thus a higher potential would be obtained at the interface. 

The results with the thiocyanate solutions indicate a fairly high zeta potential over the whole salt concentration range, the variation being between —40 and —60 mV. This is consistent with the considerably thicker foam films formed in the presence of thiocyanate ions and supports the idea that thiocyanate ions are more strongly bound to sulfoxide groups than chloride ions. 

Linkage isomers coordination modes for coordinated nitrite ion, thiocyanate ion and sulfite ion. 

Would you expect the rate of the reaction in this experiment to depend on the concentrations of both the thiocyanate ion and 2,4-dinitrobromobenzene Explain. 

The photocatalysed substitution reactions of nitroprusside ion, [Fe(CN)5(NO)], with thiocyanate ion and thiourea involve oxidation of iron(n) to iron(m). This contrasts with the reduction of cyano-complexes of iron(m) to iron(n) by thiocyanate ion noted in the previous part of this section. For the photocatalysed reactions the following mechanism is proposed ... 

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