
TY  - JOUR
A1  - Beech, TA 
A1  - Lawrence, NC 
A1  - Lincoln, SF 
T1  - Substitution reactions on arsenic(V). The formation and hydrolysis of pentaamminearsenatocobalt(III) in aqueous solution
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1973
VL  - 26
IS  - 9
SP  - 1877
EP  - 1887
KW  - 
UR  - https://doi.org/10.1071/CH9731877 
N2  - The formation of Co(NH3)5HAsO4+ and Co(NH3)5H2AsO42+ conforms to the rate law:               rate = [Co(NH3)5H2O3+](k-1[HAsO42-]+k-2[H2AsO4-])   where k-1 = (11±1)x10-2 l. mol-1 s-1 and k-2 = (120±15)x10-4 l. mol-1 s-1 at 295 K and unit ionic strength. The hydrolysis of the arsenato complex conforms to the rate law:          rate = [total arsenato complex](Ka2k1+k2[H+]+k3[H+]2)(Ka2+[H+])-1   where k1 = (290±15)x10-7s-1, k2 = (408±20)x 10-6 s-1, k3 = (670±34)x10-3 l. mol-1 s-1, and pKa2 = 3.30±0.05 at 295 K and unit ionic strength. The formation and hydrolysis reactions proceed through bond formation and cleavage between oxygen and arsenic. The mechanisms of the reactions characterized by k1 and k-1 are considered to be associative substitutions on arsenic(v), but the mechanisms of the other reactions are less certain. 
ER  -

