The reaction of hexaaquanickel(II) with hydroxide ion

The reaction of a large excess of nickel(II) sulphate and perchlorate with hydroxide ions has been studied using a stopped flow spectrophotometer. The concentrations of nickel(II) were relatively high (/<0.2M). A series of hydroxo-nickel polymers are formed immediately on mixing (< 2 ms), which increase in size with increasing hydroxide ion concentration and decreasing nickel ion concentration. These polymers then react with the excess hexaaquanickel(II) ion to form the product Ni4(OH)44+.