Structure chromium perchlorate

Chromium is unusual in that it forms a stable hexakis O-bonded urea complex. The complex was first prepared as the chloride salt by Pfeiffer804 and a crystal structure of the complex salt [Cr OC(NH2)2 6][Cr(CN)6]-2DMSO>2EtOH has recently been reported.805 Coordination at chromium(IH) is octahedral r(Cr—O) is in the range 1.96-1.98 A. The reduction of the perchlorate salt of this complex to a chromium(II) species has been studied polarographically.806 Detailed studies of the luminescence spectra of several salts of the chromium urea complex have been reported.807,808... 

Nickel in perchloric acid solution [Fig. 10(a)] has three peaks at about E = — 425 mV, E = - 200 mV, and E = - 50 mV. Similar peaks are observed on an electropolished nickel electrode [Fig. 10(b)]. The nature of the solution phase plays a role although, in chloride-containing solution, two peaks appear at E = -425 mV and E = -275 mV, but at more positive potentials a fall in capacity occurs, indicating probable formation of a layer on the electrode. On the other hand, chromium in perchloric acid solution has a quite different peak structure with a number of peaks [Fig. 10(d)]. Iron in the same solution has a single peak at about E = — 475 mV and active dissolution starts at E = — 400 mV. The stainless steel, on the other hand, seems to show features of nickel and chromium. At potentials from E = — 700 mV to E = 0 mV, the curve is similar to that of nickel while at more positive potentials, it is similar to chromium. 

The reaction of superoxotitanium(IV) with a number of substrates has been monitored by stopped-flow techniques/ In 1 M perchloric acid, the oxidation of iodide and bromide proceeded with second-order ratde constants of 1.1 x 10 M s and 2M s respectively. It is proposed that the reduction of superoxotitanium(IV) proceeds by a one-electron mechanism. Based on proton dependences, the species TiO " is more reactive than the protonated form Ti02(0H)2. The chromium chelate, bis(2-ethyl-2-hydroxybutyrato)oxochro-mate(V), is reduced by iodide, generating a Cr(IV) intermediate. The reaction is considered to proceed through formation of an iodine atom (T) for which both Cr(V) and Cr(IV) compete. In aqueous solution, [Co(EDTA)] forms a tight ion pair with I . Upon irradiation of this ion pair at 313 nm, reduction of [Co(EDTA)] to [Co(EDTA)] occurs with oxidation of 1 to IJ. The results may be interpreted on the basis of a mechanism in which [Co(EDTA)] and V are the primary photoproducts where the latter subsequently disproportionate to I3 and 1 . The kinetics and mechanism of the oxidation of 1 by a number of tetraaza macrocyclic complexes of Ni(III) have been reported. Variations in rate constants and reaction pathways are attributable to structural differences in the macrocyclic ligands. Of interest is the fact that with some of the Ni(III) complexes, spectrophotometric evidence has been obtained for an inner-sphere process with characterization of the transient [Ni(III) L(I)] intermediates. Iodide has also been used as a reductant for a nickel(III) complex of R-2-methyl-1,4,7-triazacylononane. In contrast to the square-planar macrocycles, the octahedral... 

To isolate DND, the detonation carbon is treated with strong oxidizers. This method is based on the specific feature of carbon that becomes oxidized primarily in the p -hybridized state. As for the carbon forming the diamond structure, it is in the sp -state and oxidizes at a substantially slower rate. The conditions of the treatment are chosen so as to reach the maximum possible difference between the oxidation rates of graphite and diamond. In industrial-scale production of ND, one predominantly employs liquid-phase oxidation, with mixtures of sulfuric acid and chromium anhydride or nitric acid, perchloric acid, as well as water solutions of nitric acid at elevated pressures and temperatures used as reagents. 

The probable structure of Cr(C104)2(N2H4)2-C104 has an octahedral chromium bonded to two nitrogen atoms of hydrazine and four oxygen atoms of two perchlorate groups (Figure 3.18). 

Figure 3.18 Structure of diperchlorate dihydrazine chromium(III) perchlorate. Ph.D Thesis of Nesamani, C. under Prof. K. C. Patil at Indian Institute of Science.

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