aluminium in solid liquid Br2 was dropped into a solid mixt. of oxide and a large excess ofAl powder in one-end sealed quartz tube under Ar atm., evacuated, seale d, placed in a tabular furnace with temp. gradient from 750 to 460 K;

aluminium in solid Ln2O3, AlBr3 (Ln:Al = 1:4) and Al powder were placed into an one-end sealed quartz tube under Ar, sealed under vac., heated at 600 K for 1 h; sealed tube was placed in a tubular furnace with a reduced temp. gradient from 750 to 460 K, vapor transport reaction for 6 h, tube was quicklyremoved from the furnace, the hot end was quenched with water, AlBr3 wa s condensed;

sublimation in Ta-vessel;

in hydrogen bromide oxide dissoln. in dil HBr (1:3), soln. evapn. until crystn. occured; crystals sepn. from mother liquor, drying (vac. desiccator, over CaCl2, P2O5 and alkali) to const. mass;

in hydrogen bromide aq. HBr; all operations under Ar; Gd2O3 dissolved in aq. HBr, NH4Br added, heated in vac. (ratio of heating 5°C/h) to 200°C, then with 12°C/h to 400°C to dryness; purifn. by distn. in a Ta vessel in high vac. (1E-5 mbar);

HBr vapor, at higher temp.;