1864.] Prof. A. H. Church on certain Ethylphosphates, 



521 



of the methylsulphuric, phenylsulphurous, nitrophenylsulphous and other 

 series, but have lately turned my attention to the analogous compounds of 

 the phosphoric series. Some remarkable substances have been thus made, 

 their constitution seeming to have a direct bearing upon the important 

 question of the atomicity and equivalency of certain of the metallic elements. 



Several substances might have served as starting-points for these new 

 inquiries. A curious compound, phenylphosphorie acid, Cg Hg POj^, 

 was prepared ; but its instability, and the oxidation to which it and its salts 

 are liable, rendered it unsuited for the present purpose. I intend to 

 describe in the present paper but one series of salts, formed from Pelouze's 

 ethylphosphoric acid, Hg PO^. This compound, containing two atoms 

 of easily replaceable hydrogen, appeared admirably adapted for the pur- 

 pose in view. It is readily prepared by digesting (for 48 hours) finely 

 crushed glacial phosphoric acid with alcohol of 90 per cent. : — 



^^g^-j0 + HP03= H IpO,. 



From the ethylphosphoric acid thus formed the barium salt was prepared 

 in large quantity and of perfect purity. This compound, Hg, Bag, PO^ 

 -J- 6 Hg O, is remarkable for being less soluble in boiling water than in 

 water at 70° C, or even at 15° — a characteristic property of several other 

 ethylphosphates. Boiling water, in fact, affects this barium salt in a peculiar 

 manner. If to its boiling saturated solution a quantity of the ordinary 

 crystallized salt be added, the crystals instantly assume a pearly aspect, 

 and are found, after having been filtered off, washed once with boiling 

 water, and dried in vacuo over sulphuric acid, to have lost 5 H2 O, and 

 thus to have the formula 



C,Hg, Ba„ PO, + Aq. 



They thus contain the proportion of water found in the majority of the 

 ethylphosphates. When, on the other hand, cold water is poured on these 

 crystals, or on the salt dried at 100°, the lost water is regained, the nacreous 

 aspect of the dried salt disappears, while a great increase in its bulk occurs. 



From the barium salt the lead and silver compounds are readily made. 

 To a solution of ethylphosphate of barium nearly saturated at 70°, acetate 

 of lead or nitrate of silver is added in slight excess, the liquid allowed 

 to cool and then filtered. The collected precipitate is to be washed with 

 cold water. The lead salt may be obtained anhydrous by heating it to 

 130°-150°: it is almost insoluble in cold water, but is slightly soluble in 

 hot water, from which it may be crystallized. The silver salt dissolves to 

 some extent in hot water, and separates in pearly plates as the liquid cools. 

 It is blackened, especially when moist, on exposure to dayhght. . Dried in 



The following are the atomic weights adopted : — C = 12, = 16, IIg=200 ; I have 

 provisionally retained for Ag, Ba, Pb, &c. the lower a,toniic weights till, lately in 

 general use. - , . 



2 R 2 



