108 



Fig. 10. Boroliydrogen. 



to four HH,-gioii|is, wliich af tlie same liTiie lias taken up an electron 



witli H-nucleus, the relative sta- 

 bility and the fact that this boro- 

 h.ydrogen dissolves in KOH without 

 residue, evidently with formation 

 of a salt, has been explained in 

 a satisfactory waj. Its formula 

 is, therefore, H[B(BH,)J with one 

 penta-valent and four tri-valent 

 boron atoms. 



In the boro-alkjl compounds 

 transition of an H-atom into the 

 ion-condition is not possible' B(CH,), has been separated, and a 

 polymerisation to [B(CH,),], has not been observed — also boro- 

 triplienyl was lately prepared. 



That the horo-alkyl compounds can combine with ammonia ') can 

 be explained in entirely the same way as for BF, (cf. p. J03), there 

 is sutHicient reason in these non-polarly bound molecules to assume 

 the boron, just as the niti'Ogen, to be letra-valent. 



Boro-nitrocien. HN. It has not been possible so far to melt, this 

 substance, which forms a white |)Owder and wliich is \ery 

 resistant against the action of the air also at high teinperatnie, for 

 which reasons it has been proposed as material for lire proof recept- 

 acles ; it is very inteiesting as far as the considerations given here 

 are concerned. In appearance the demand of the valency has been 

 completely fultilled, as the tri-valent nitrogen is combined with the 

 tri-valent boron. When, however, the properties of nitrogen com- 

 pounds of other light elements, as cyanogen gas, halogen nitrogen 

 compounds, etc. are considered, boro-nilrogen must at any rate be 

 assumed to be very far |)olymerized. 



When every nitrogen atom is supposed to be suri-ounded by three 

 boron atoms, and these again each bound to three nitrogen atoms 

 aiui so on, two electrons of every nitrogen alom remain available 

 in the outer shell for a non-polar bond. Inversely every boron atom 

 can be joined by a pair of electrons. This mutual saturation is liei'e 

 exceedingly probable, because then at the same time an exceptionally 

 stable structure can be attained, \iz. that of the caiboii in diamond. 

 The properties of boron nitrogen lead ns at any rate to expect 



') Berichte 54 B 531 (192^). The ammonia compound of boro-trimethyl is a 

 volatile well-crystallizing compound, much more stable when exposed to the air 

 than B(^GH3)3 itself. 



