326 M. C. Lea — Silver Hemisulphaie. 



It is possible that the silver phosphate ma} 7 be combined in 

 definite proportions and the approach to uniformity of com- 

 position somewhat favors this idea. But such a view would 

 require the assumption of a large, perhaps too large a molecule. 



Analyses. 



A. Material prepared from silver carbonate and dried at 

 100° C. 



(1) (2) Mean. 



Ag 76-13 76-75 76-44 



O ...: 3-29 3-29 



P„0 6 2-30 209 2-19 



S0 3 .\ 16-19 16-47 16-33 



Water 1-78 1-78 



99-69 10003 



B. Material prepared by various other methods considered 

 less reliable. 





Determinations. 







Ag per cent. 



P.2O5. S0 3 . 





O. 



j 78-59 

 j 78-45 







3-93 







3-69 



77-16 







3-61 



( 75-43 



2-18 15-61 





3-29 



•1 75-46 







3-25 



( 75-35 



1-77 







Mean 76-74 



Mean 



3-55 



The determinations of phosphoric and of sulphuric anhy- 

 dride are placed opposite the silver determinations to which 

 they belong. The oxygen determinations are distinct. 



The most reasonable interpretation of these results is that 

 we have to do with a double sulphate of silver hemioxide and 

 protoxide in which a portion of the sulphuric acid is replaced 

 by phosphoric. The proportion of phosphoric acid seems to 

 be nearly constant, three concordant analyses having given 

 2*09, 2*30, and 2-18, with a mean of 2-19. These proportions 

 may be expressed by the formula 



f (AgjSO.Ag.SO.H.O) + Ag.P0 4 Ag,P0 4 . 



The comparison of this formula with results obtained is as 

 follows : 



