Chromium, hexaaqua

Chromium, hexaammine-hexacyanocobaltate coordination isomerism, 183 trioxalatoaluminum reactions, 27 Chromium, hexaaqua-electron transfer, 367 with hexaaquachromium, 370 with pentaamineisonicotinamidoruthenium, 367 with pentaaquahydroxychromium, 370 isomerism, 183 trichloride isomerism, 183 Chromium, hexacyano-hexamminecobaltate coordination isomerism, 183 ligand field photochemistry, 398 photochemistry excited states, 398... 

Chromium(III) has a ground state in pseudo-octahedral symmetry. The absence of low-lying excited states excludes fast electron relaxation, which is in fact of the order of 10 -10 ° s. The main electron relaxation mechanism is ascribed to the modulation of transient ZFS. Figure 18 shows the NMRD profiles of hexaaqua chromium(III) at different temperatures (62). The position of the first dispersion, in the 333 K profile, indicates a correlation time of 5 X 10 ° s. Since it is too long to be the reorientational time and too fast to be the water proton lifetime, it must correspond to the electron relaxation time, and such a dispersion must be due to contact relaxation. The high field dispersion is the oos dispersion due to dipolar relaxation, modulated by the reorientational correlation time = 3 x 10 s. According to the Stokes-Einstein law, increases with decreasing temperature, and... 

The hexaaqua ion, [Cr(OH2)6]3+, is also the final product in the reduction process (7, 12). The complete process using Fe(II) as a reducing agent is shown in the reaction sequence (8)-(ll), where a Fenton-type (15) mechanism is proposed (7,16), with [(H20)5CrIV0]2+ behaving as the chromium equivalent of the -OH radical (16). 

Chromium Complexes. Because of their high stability chromium complexes of tri-dentate azo dyes are the most important class of metal-complex dyes. This is due to the reluctance of hexacoordinated chromium(m) complexes to exchange ligands, which, however, complicates the preparation of chromium complex dyes from hexaaqua chromium(m) salts, and makes it possible to prepare triaqua 1 1 chromium complex dyes. Generally, 1 1 chromium complexes can be made in... 

S3BHKN6C12H15, Borate(l-), hydrotris(methi-mazolyl)-, potassium, 33 200 SsCgHig, Cyclododecane, 1,5,9-trithia-, 33 120 S3CrOi5C2iH33, Chromium(III), hexaaqua-, tris(p-toluenesulfonate), 33 97 S3EUF9N8O14C24H34, Europium(lll), l-(4-nitro-benzyl)-4,7,10-tris(carbamoyhnethyl)-1,4,7,10-tetraazacyclododecane-, 33 217 S3Fe09C2iH2i, Iron(III), tris(p-toluene-sulfonate), 33 99... 

Homolysis (6.4.5) is a reversible reaction and, in excess of the hexaaqua-chromium(II) ions, the only reaction that follows is acidolysis. If the substrate considered reacts fast enough with Cr(H20)6 and with the radical, the rate constant becomes the sum of (acidolysis) and (homolysis). 

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