Co ammines

The uptake-pH surveys of a number of other metals (Ru(II), Ru(III), Co, and Ni beyond Cu, Pt and Pd) over amorphous and mesoporous silica have recently been reported [24]. It is beheved in all cases that adsorption is all or mostly electrostatic, with minor deviations due to metaldispersed particles form (with the exception once again of Co since Co ammines reduce on silica only at temperatures in excess of 700 C, where sintering cannot be prevented). DI, on the other hand, yielded much larger particles for all metals over both types of supports. 

Since it is known that OH does not in fact attack co-ordinated ammonia, a rapid dissociation of the Co ammine complex followed by attack by this radical on the ammonia released would then account for the formation of NHa radicals. The reaction products are NH4+, Ng, N2O, and a relatively small amount of Oj. The yields of N2 and NjO are close to those expected if NH2OH were the intermediate giving rise to these gases. An interesting overlap on these studies is provided by data on the rate of detachment of NH3 from cobaIt(in) complexes reduced by pulse radiolysis. The rate constant Atq = 8 x lO 1 moI s for the process... 

Reduced halogens. The higher oxides and hydroxides, also Co, release X2 and possibly CI2O from HX, with warming if need be, forming Co but HCl does not reduce Co ammines or [Co(CN)e]. ... 

Oxidation. Reagents Mn04 and Pb02 oxidize Co° ammines to Co , somewhat similarly to the action of O2 or H2O2, which see. This prevents cobalt s precipitation by OH (separation from nickel). 

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