acetonitrile in acetonitrile 10 min; filtered, concd., Et2O was added, cooled to -20°C, recrystd. from acetonitrile-ether and dried in a stream of N2;

in diethyl ether; acetonitrile crystn.;

in acetonitrile byproducts: NO; N2; metallic silver added to suspn. of NOBF4; stirred for 0.5 h at 25-30°C, 0.5 h at 45-55°C, 15 min at 75-85°C; filtered; cooled to -5°C; filtered off; washed (dry ether); reprecipitated from mixt. of CH3CN and ether; elem.anal.;