USE OF CHROMIUM(4) DIPEROXOAMINES IN SYNTHESIS OF CHROMIUM(3)-AMINE COMPLEXES .V. HYDROLYSIS PRODUCTS OF DICHLORO- AND DIBROMOAQUOTRIAMMINECHROMIUM(3) CATIONS

The reaction between Cr(NH3)3(O2)2 and 12 FHCl, originally thought to produce two forms (violet and green) of [Cr(NH3)3- (OH2)Cl2] Cl, has been reinvestigated. The green form is shown by X-ray powder diffraction to be a mixture of the violet form and green Cr(NH3)3Cl3. The diperoxide also reacts with 63% HBr to give a mixture of green [Cr(NH3)3(OH2)Br2]Br and violet [Cr(NH3)3(OH2)2Br]Br2. On the basis of hydrolysis rates, visible absorption spectra, and ion-exchange properties, the blue Cr(NH3)3(OH2)Cl+2 and green Cr(NH3)3(OH2)Br+2 cations are assigned a fraws-dihalo-fraws-triammine structure. Using ion-exchange chromatography, the magenta trans-haloaquo-trans-triammine Cr(NH3)3(OH2)2Cl+2 and Cr(NH3)3- (OH2)2Br+2 cations have been isolated and characterized in solution. The final hydrolysis product from these halo ions is the trans-Cr(NH3)3(OH2)3+3 ion. Visible absorption spectra are presented for these cations. © 1969, American Chemical Society. All rights reserved.