Wohler and Deville on some properties of Boron. Ill 



method, which has already furnished them 500 or 600 grammes 

 of this substance. 100 grms. of boracic acid, fused and coarsely 

 powdered, are mixed with 60 grms. of sodium, and the mixture 

 projected into a red-hot iron crucible. The whole is covered with 

 40 or 50 grms. of fused salt, the crucible closed, and when the 

 action is over, the contents stirred about with an iron red. The 

 mass, which contains boron swimming in a flux of boracic acid, 

 borate of soda, and chloride of sodium, is poured, while still hot, 

 into water acidulated with hydrochloric acid, then washed on a 

 filter, first with acidulated water until free from boracic acid, and 

 finally with distilled water. The boron remains on the filter and 

 is dried in the air on porous tiles. 



AMien amorphous boron is heated in a current of ammonia, it 

 appears to take fire, incandescence ensues, and the ammonia is 

 decomposed, the nitrogen combining with the boron to form 

 nitride of boron, and the hydrogen escaping. Boron, or a mix- 

 ture of boracic acid and charcoal strongly heated in a current of 

 pure nitrogen, is entirely converted into nitride of boron. Boron 

 caimot therefore be heated in crucibles in ordinary furnaces 

 without being changed into nitride. Amorphous boron may be 

 readily converted into crystallized boron by lining a crucible 

 with amorphous boron, and placing in the cavity a piece of alu- 

 minium. At an elevated temperature the aluminium becomes 

 charged with boron, which crystallizes out on cooling, and may 

 be obtained by dissolving the aluminium either in soda or in 

 hydrochloric acid. To prevent the boron from absorbing ni- 

 trogen, the crucible containing it is placed inside another ci'u- 

 cible, lined with a mixture of titanic acid and charcoal, which 

 stops both the nitrogen and the oxygen. 



At a full red heat boron decomposes the vapour of water, with 

 the production of hydrogen and boracic acid. Part of the boracic 

 acid volatilizes with the vapour of water, and crystallizes at some 

 distance from the point at which the tube in which the experi- 

 ment was made is heated. 



When heated in sulphuretted hydrogen, boron combines with 

 the sulphur, hydrogen being liberated, and the sulphide of boron 

 volatilizes in the excess of sulphuretted hydrogen, just as boracic 

 acid in the vapour of water; and the sulphide of boron is ob- 

 tained crystallized at some distance from the point at which it is 

 formed. 



At a very moderate temperature hydrochloric acid gas is de- 

 composed by boron, with evolution of light and formation of 

 chloride of boron ; and bromide of boron is similarly obtained. 

 The chloride and bromide of boron are not gases, as generally 

 staled, but liquids, of which the first boils at 17° and the latter 

 at 00" C. 



