207683-22-5

This gravimetric reagent for Cs is purified by passing a solution (10g in 100mL H2O) through a column of Dowex 50Wx4 (Na form) and eluting with dilute NaCl. Extract the 250-275mL eluate with Et2O (3 x 50mL), add dry xylene (200mL), evaporate the Et2O off in vacuo, immerse the xylene in a bath at 50o and the salt crystallises out. It is hygroscopic. [Moore et al. Anal Chim Acta 35 1 1966, Tsubouci et al. Anal Chem 57 783 1985.]