On Phosphonium Chloride. 



283 



April 21, 1887. 



Professor STOKES, D.C.L., President, in the Chair. 



The Presents received were laid on the table, and thanks ordered 

 for them. 



The following Papers were read : — 



I. "On Phosphonium Chloride." By Sidney Skinner, B.A., 

 Scholar of Christ's College, Cambridge. Communicated by 

 Professor Dewar, F.R.S. Received March 28, 1887. 



At the close of an interesting paper in the ' Annales de Chimie,' 

 vol. 20, 1880, Ogier describes the preparation of the componnd 

 phosphonium chloride. When the two gases phosphine and hydro- 

 chloric acid are mixed at 14° C. under atmospheric pressure they do 

 not combine; but when the pressure is raised to 20 atmospheres 

 small crystals of the compound PH 4 C1 form at the upper end of the 

 tube. At 26° 0. these crystals melt, and the liquid formed was shown 

 by some later experiments of van't Hoff ('Deutsch. Chem. Gesell. 

 J3er.,' Jahrg. 18, p. 2088) to reach the critical state about 50°. This 

 was the extent of our knowledge when the following experiments 

 were begun with a view to examine more exactly this dissociable 

 process, (1) in regard to its relations to temperature, volume, and 

 pressure, and to those of the separate gases PH 3 and HC1 ; (2) in 

 regard to the thermal changes involved in the formation of the 

 compound. 



This paper deals with the first part of the research only, but owing 

 to the interesting results which it contains there can be little 

 hesitation in putting it forth. 



Experiments on Phosphonium Chloride. 



Phosphine was prepared by dropping strong potash solution on a 

 mixture of broken glass and phosphoniam iodide. After leaving the 

 flask in which this operation was conducted the gas passed through a 

 tube containing moist broken glass kept at the temperature of 

 melting ice, and then through a drying tube of CaCl 2 and Pg0 5 . The 

 gas was collected in tubes over mercury. The hydrochloric acid gas 

 was prepared from strong sulphuric acid and ammonium chloride. 

 To obtain a mixture of equal volumes of these two gases, a pipette 



vol. xlii. Y 



