THE ACTION OF SODIUM THIOSULPHATE SOLU- 
TIONS ON CERTAIN SILVER SALTS. 
BY W. M. BARR. 
The following work was undertaken at the suggestion of 
Dr. W. S. Hendrixson, to whom I am indebted for advice 
and assistance in the work. 
The solvent action of the thiosulphates on the halides of 
silver has long been known, and the fact is almost daily 
turned to account in the laboratory, and though the reac- 
tion has been quantitatively studied to some extent, an 
examination of the literature shows that no very satis- 
factory theory of the nature of the reaction and the 
complexes formed in solution has been established. 
Rosenheim and Steinhauser * isolated definite compounds 
by evaporating saturated solutions of thiosulphates con- 
taining all the silver chloride or silver bromide they would 
dissolve (a compound of definite compositions was not 
obtained with Ag I), but this does not prove that similar 
salts are formed in more dilute thiosulphate solutions. 
Barth f has proposed for the reaction which takes place in 
such dilute solutions 3 Na 2 S 2 0 3 + 2 Ag (Cl. Br. I) = (Ag 
Na S 2 0 3 ) a Na 2 S 2 0 3 + 2 Na (Cl. Br. I). 
By the solubility determinations of Valenta J it is ap- 
parent that the results, even in the case of the chloride, 
do not accord with the above equation, the amount of 
chloride being too small to satisfy the equation, the same 
*Zeit. Anorg. Chem. 25: 72 and 103. 
t Zeit. Phys. Chem. 9 : 176. 
jBerichte der Weiner Acad. 108; Abt. 11 b. 
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