Johnson—The Chemistry of Boron 
529 
pounds boron is trivalent instead of tetravalent as is the case 
with carbon and silicon compounds. In the latter property 
boron is more like tbe members of tbe nitrogen group, in fact 
there is some evidence that it may act as a pentavalent element 
in certain compounds. Theoretically, boron should act very 
much like aluminum also. Notwithstanding, excepting the ox¬ 
ide Bo 0 3 , there are not so very many close analogies. In fact 
there is a very decided similarity to the tri- and pentavalent 
elements, nitrogen and phosphorous, in chemical behavior, ah 
though they are decidedly non-metallic elements. And strange 
enough, though boron must be regarded as more of a non-metal 
than a metal vet it reacts far more readily with non-metals than 
metals; borides of metals are very difficult to prepare. 
Among the very few inorganic compounds of importance are 
the halogen borides. These were merely prepared by several 
workers but not studied to any extent. Their chemical com¬ 
portment toward other reagents has remained a virgin field. 
B 01 3 * is a liquid boiling at 20° ; B Br 3 boils at 91°; and B I 3 
boils at 210°. The latter compound is decomposed quite read¬ 
ily by light. B Br 3 on account of its stability and high boiling 
point has been taken as starting material for the synthesis of 
boron compounds in my work. The action of all the halogen 
compounds, which are being prepared from time to time by the 
combustion method as needed in my work, toward typical or¬ 
ganic and inorganic compounds, and their physico-chemical 
properties, as indexes of refraction, latent heat of vaporization, 
etc., are being studied and will soon be reported on in a separate 
paper. 
Tn studying the chemical comportment of the halogen bor¬ 
ides, the tetrahalogen compounds of carbon and silicon on one 
hand, of phosphorus and nitrogen on the other, and also of 
aluminum have been kept steadily in mind. That is for prac¬ 
tical purposes, I regard boron as occupying the center of a tri¬ 
angular field bounded by the above mentioned groups of ele¬ 
ments and aluminum. 
* Nickles—C.» R. 60-800-1865; Moissan—C. R. 112-717-1891; Besson 
—C. R. 118-78-1891. 
