NOVEMBER, 1952 8.
GALLIUM
Our knowledge of the chemistry of the organa-gallium compounds is very limited. These compounds are studied rather more readily than the correspondmg boron compounds because the dialkylgallium halides do not ammo~olyzein liquid ammonia. T ~ n ~ ~ l h v l n u l l i zTrimeth\~lenllium ~n~. " boils a t 55.7" and freezes a t -19". It is pyrophoric and the solid ignites in air a t -76O. It is readily chlorinated to the mono or the dichloride by HCl in ether. The gallane forms a monoetherate which boils a t 98.0'; the etherate vapor is dissociated to the extent of about 70 per cent at 25". One methyl group of trimethylgallium monoetherate is hydrolyzed by potassium hydroxide a t 25', while two methyl groups are hydrolyzed a t 100". The gallane forms the ammiue MeaGa.NH3which melts a t 31" and sublimes in vaeuo a t room temperature. Two molecules of trimethylgallium ammine react with one molecule of sodium amide to form bistrimethyl
