1864.] Prof. A. H. Church on certain EtJiylphosphates. 529 



The arsenic in the arsenious ethylphosphate was determined as sulphide, 

 the precipitation being effected according to the directions given by Fre- 

 senius. The salt was dried by pressure between folds of filter-paper, it 

 was then placed in vacuo over sulphuric acid, and finally heated for a short 

 time in the water-oven. The arsenious sulphide obtained on its analysis 

 was dried at 100° C. 



I. 1-347 grm. gave '639 grm. of As^ S3. 



II. '591 grm. gave '29 grm. of As^ S3. 



The formula (C^ Hg)3 xis^ SPO^ requires 28*74 per cent, of arsenic: 

 analysis I. gave 28*95, while II. gave 29*58, the specimen of salt sub- 

 mitted to analysis in the latter case having been partially decomposed by 

 washing, ethylphosphoric acid being thus removed, and consequently an 

 excess of arsenious anhydride remaining in the residual salt. 



The ease with which the arsenious ethylphosphate is formed induced me 

 to hope that similar success would attend experiments made with another 

 triatomic element, phosphorus. When an action is established between 

 terchloride of phosphorus and ethylphosphate of silver, an oily product 

 may be removed from the mass by means of anhydrous ether, but it yields 

 on analysis results less definite than could be wished. Yet the reaction is 

 a promising one : I hope to recur to it shortly, and to experiment in a 

 similar manner with antimony and bismuth compounds. 



Bitetr ethyliac Ethylphosphate.— ordinary ethylphosphate of ammo- 

 nium is very readily made ; its aqueous solution becomes acid on evapora- 

 tion, but the salt may be obtained in a semicrystalline form by drying its 

 saturated solution in vacuo over sulphuric acid. The salt heated carefully 

 in an oil-bath for some time loses ammonia as well as water, but yet appears 

 to yield, among other products, ethylphosphamic acid. A different and 

 much more definite kind of decomposition takes place with the compound 

 next to be described. 



When a hot solution of argentic ethylphosphate is mixed with a solu- 

 tion of iodide of tetrethylium, a change occurs expressed by the equation 



C,H„Ag„P0, + 2[(aH,),NI]=C,H„ [(C, H,), N]„ P0,-h2Ag 1. 

 If the two salts be employed in the exact proportions indicated by this 

 equation, it will be found that after boiling them together the new com- 

 pound is contained in the filtrate. On evaporating this liquid first of all 

 at 100°, and then in vacuo over sulphuric acid, a syrup, and finally a 

 mass of confused crystals will be obtained ; by long drying, these crystals 

 lose their transparency, most probably because they have thus parted with 

 some of their water of crystallization. The salt is intensely soluble in cold 

 water, and deliquescent. The analyses of this salt were not exact, but 

 corresponded sufficiently with the formula of an ethylphosphoric acid in 

 which two atoms of hydrogen had been replaced by two atoms of tetrethy- 

 lium. This view of its constitution is amply confirmed, not only by the 

 mode in which the salt is prepared, but also by a singular decomposition 



