in further solvent(s) addn. of 350 g Br2 to a mixt. of 300 g PBr2 and 250 g NH4Br in 450 ml (CHCl2)2 at 110-120 °C; heating at 145-155 °C for 2-3 days; colling; removal of remained NH4Br;; removal of the solvent at 35-40 °C and 2 Torr; removal of the oily compound of the crude product; sublimation at 130-160 °C and 0.05-0.5 Torr forming a mixt. of with more (NPBr2)3 than (NPBr2)4; fractional distn., chromatography (Al2O3);;

in further solvent(s) react. of PBr5 with NH4Br in (CHCl2)2 under addn. of consumed NH4Br;; distg. off the solvent; recrystn. of the crystal mass from C6H6; formation of a mixt. of (NPBr2)3 and (NPBr2)4; isolation on sampling the crystals of each compound;;

in neat (no solvent) byproducts: KBr, N2; warming up to 145°C during 3 h with stirring, keeping for 18 h at this temp.; hot filtration, sepn. of KBr by distn., extg. the residue twice with benzene under reflux, vacuum distn., vacuum sublimation yields products in 11:5:1 ratio for trimer, tetramer and pentamer, identification by thin layer chromy. and (31)P-NMR;