in neat (no solvent) passing a vigorous stream of high purity H2 through melting NaHCO2 containing 3percent NaOH at 260-320°C for 1-1.5h; solidification;;
in water at 100°C; filtration of boiling soln.; pptn.;; pure product on washing with boiling H2O; product obtained by pptn. during cooling the filtrate to 20°C contains (NH4)2C2O4;;
