1 g of copper sulfate pentahydrate and 1.8 g of ammonium persulphate are dissolved separately in 8 mL of water, then combined. A slow addition with vigorous stirring of 3.2 mL of pyridine is started, the mixture is filtered and washed with water. The resulting residue is dried at 35 ° C for a few hours.
2 CuSO4 · 5H2O + 8 C5H5N + 2 (NH4)2S2O8 = 2 [Cu(C5H5N)4]S2O8 + 2 (NH4)2SO4 + 5 H2O
The mixture of complete addition
The dried product