606 



the very high boiling-point of the resulting compound, in consequence 

 of which the vapour of the latter can exert but a very slight tension 

 at the common temperature, I am induced to think that the phos- 

 phorus-base may be used in many cases for the volumetric estimation 

 of oxygen. When a paper ball soaked in triethylphosphine is passed 

 up in a portion of air confined over mercury, the mercury immedi- 

 ately begins to rise, and continues to do so for about two hours, after 

 which the volume becomes constant, the diminution corresponding 

 very nearly to the proportion of oxygen in the air. To obtain very 

 exact results, however, it would be probably necessary in every case 

 to remove the residual vapour of triethylphosphine by means of a 

 ball saturated with sulphuric acid. 



Oxide of triethylphosphine exhibits in general but a small tendency 

 to unite with other bodies. Nevertheless it forms crystalline com- 

 pounds with iodide and bromide of zinc. I have examined more 

 particularly the iodine-compound. 



Oxide of Triethylphosphine and Iodide of Zinc. On mixing the 

 solutions of the two bodies, the compound separates, either as a 

 crystalline precipitate or in oily drops which soon solidify with 

 crystalline structure. It is easily purified by recrystallization from 

 alcohol, when it is deposited in often well-formed monoclinic crystals 

 containing ^ R p() Znl = ^ jj^ pQ) Znl 



It is remarkable that this compound formed in presence of a large 

 excess of hydriodic and even of hydrochloric acid. 



Oxide of Triethylphosphine and Dichloride of Platinum. No pre- 

 cipitate is formed on mixing the aqueous solutions of the two com- 

 pounds, however concentrated. But on adding the anhydrous oxide 

 to a concentrated solution of dichloride of platinum in absolute 

 alcohol, a crystalline platinum-compound is deposited after a few 

 moments. This compound is exceedingly soluble in water, easily 

 soluble in alcohol, insoluble in ether. On adding ether to the 

 alcoholic solution, the salt is precipitated, although with difficulty, 

 in the crystalline state. The alcoholic solution, when evaporating 

 spontaneously, yields beautiful hexagonal plates of the monoclinic 

 system, frequently of very considerable dimensions. The crystals 

 have the rather complex formula 



C H B P, 3 Yi, C1. = 3[(C, H,), PO] + (C, H.), PCI,, 2Pt CI,. 





