Sulfato complexes formation

Forsterling, H.-D. Stuk, L. 1992. Effects of Ce /Sulfato Complex Formation in the Belousov Zhabotinskii Reaction ESR Studies of Malonyl Radical Formation, J. Phys. Chem. 96, 3067-3072. 

X-Ray diffraction studies of aqueous CdS04 solutions have clearly demonstrated the formation of O-sulfato complexes.668-670 These are of the general form [Cd(H20)6- (0S03) ](2-2")+, and appear to be the major species present in concentrated solutions. These results are fully in accord with tensimetric studies of the cadmium and magnesium sulfate aqueous systems, which indicate an increased interionic attraction at elevated temperatures.671 In contrast, X-ray diffraction studies on cadmium perchlorate solutions show no evidence for the coordination of the perchlorate ion to the metal, the only cationic species present being [Cd(H20)6]2+(Cd—O, 2.292 A, cf. Cd—O, 2.292 A in solid [Cd(H20)6][C104]2),670... 

Similarly some degree (5-10% of the reported concentrations) of complex formation might be expected for such metal ions as magnesium or cobalt (II), but apparently there are no examples of extensive sulfato entities. 

Reactions and mass action - The reactions for the formation of the aluminium-sulfato complexes (Table 5.3) are... 

Figure 4. Section of the pseudobinary phase diagram of the sulfuric acid SLP catalytic material. The data were taken from Ref. 16. The data points were derived from anomalies of the conductivity versus temperature curves of the respective mixtures. At the high compositional resolution and in the range of the global eutectic, the formation of a vanadate-sulfato complex causes the local maximum in the solidus curve. It is noted that extreme precision in the experimental procedures was necessary to derive this result illustrating the characteristic of fused systems that compound formation can well occur in the molten state.

Reduction of [CoWi204o] by SOj leads to SjOg" under conditions of excess reductant. The mechanism involves three pathways with HSOf, SO , and S20 as reductants. Under conditions of excess oxidant, significant amounts of S04 are also produced. Sulfite catalyzes the autoxida-tion of cobalt(II) in azide media, and the iron(III)/(II) catalyzed reaction has an important role in the cycling of iron in the atmosphere. The nickel(III) complex [Ni([14]aneN4)] catalyzes the autoxidation of SO2 in a reaction in which generation of SOf is rate-limiting. " A dependence on [H is noted, and the rate constant for the acid-independent pathway is 41 Af s The fi-oxo derivative [(TPP)Fe—O—Fe(TPP)] shows similar behavior and results in the formation of the /i-sulfato complex. ... 

The structure of mer-Mo(CO)3(S02)(PPr 3)2 was found to contain j -planar rather than if SO2 geometry. The phosphines are mutually trans, and the rotational orientation is such that the S-O and M-CO bonds eclipse one another. Although the M-S bond is the longest reported for / -planar SO2, the SO2 is not labile. The complex reacts with molecular oxygen in solution with decomposition rather than sulfato formation. 

MS02 complexes. The / -planar, -pyramidal, and tf geometries are identifiable on the basis of infrared frequencies. The >/ -planar complexes, without exception, are stable toward sulfate formation and contain tightly bound SO2. With exception of RhCl(ttp)(S02), the -pyramidal complexes form sulfato products and possess labile SO2 as do the rf complexes. 

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