865.] Messrs. Buckton and (Ming on Aluminium Compounds. 21 



di-oxyethide. But the iodo- derivatives and oxidation products have as yet 

 been submitted to a preliminary examination only. 



Aluminium Methide. 



This compound was obtained by a process strictly analogous to that which 

 yielded us aluminium ethide. On heating mercuric methide with alumi- 

 nium-clippings in a water-bath, the replacement of the mercury by alumi- 

 nium took place with even greater facility than was manifested during the 

 similar treatment of the ethylated body. After a single distillation, alumi- 

 nium methide occurred as a colourless mobile liquid, boiling steadily at 130, 

 and solidifying a few degrees above into a beautiful transparent crystal- 

 line mass. The liquid took fire spontaneously on exposure to air, burning 

 with a very smoky flame, and producing abundant flocculi of alumina dis- 

 coloured by soot. On analysis, aluminium methide gave 48*4 per cent, of 

 carbon, 12'3 per cent, hydrogen, and 38' 2 per cent, aluminium, numbers 

 which are quite sufficiently in accordance with the formula AlMe 3 , or 

 A1 2 Me 8 . Three separate determinations of vapour-density, made at the 

 temperatures of 240, 220, and 220, the last with hydrogen in the tube, 

 gave the numbers 2-80, 2*80, and 2'81 respectively, which agree closely 

 with the theoretical number calculated for the formula Al Me 3 , namely 2 '5. 

 But the corrected density increased very rapidly with every decrease of 

 temperature, a peculiarity of behaviour also noticed by Frankland in the 

 case of boric methide. Thus three separate determinations, made at 163, 

 160, and 162, the last with hydrogen in the tube, gave the densities 4'1, 

 4'1, and 3'9 respectively; while the determinations made at the boiling- 

 point of aluminium methide, of course with hydrogen in the tube, as re- 

 commended by Playfair and Wanklyn, gave the densities 4'36 and 4'40 

 respectively, which approximate somewhat to the theoretical density 5'0, 

 calculated for the formula Al 2 Me 8 . Hence aluminium methide appears 

 to be a member of that class of bodies whose vapour-densities are under 

 certain circumstances anomalous, either because the bodies exist in two 

 molecular states of condensation, or because their vapours are not possessed 

 of perfect elasticity until heated considerably above the boiling-points of 

 the respective liquids. In either case the question naturally presents itself, 

 May not the only observed vapour-density of aluminic chloride correspond 

 to the high vapour-density of aluminium methide, and may they not both 

 be equally anomalous, and consequently untrustworthy as a basis for deter- 

 mining the general formulae of aluminic compounds? 



