234 C. 13. and J. B. Bhaduri — On Double Thiosulphates [No. 1, 



Contribution from the Chemical Laboratory, Presidency College, Calcutta. 

 On Double Thiosulphates of Copper and Sodium. — By Chandra 

 Bhushan BHADURr, B.A., and Jyoti Bhushan Bhaduri, M.A. 

 Prem Chand Roychand Scholar. Communicated by Alex. Pedler, 

 F.R.S. 



CONTENTS. 



Page. 



Introduction ... ... ... ... ... 234 



... 234, 



... 235 



... 244 



... 246 



... 246 



Historical note ... 



Yellow double thiosulphates 



Action of cuprous oxide on sodium thiosulphate 



White double thiosulphate with sodium chloride 



Yellowish white double thiosulphate ... 



When working with the preparation of a few normal sulphites and 

 particularly during an attempt to prepare normal cuprous and cupric 

 sulphites, we had occasionally to use sodium thiosulphate instead of 

 sodium sulphite or sulphur dioxide dissolved in water. It was soon 

 found that a beautiful yellow salt separates, on allowing a mixture of 

 sodium thiosulphate and copper sulphate solutions to stand for some 

 time, in microscopic needles which however decomposes readily in a day 

 or two unless special care is taken to get it perfectly dry. By varying 

 the concentration and proportion, with or without addition of alcohol, 

 the colour of the salts obtained seemed to change considerably. We 

 undertook to analyse some of them, and the result of the analyses forms 

 the subject matter of the present paper. 



But before proceeding to describe our work a brief notice of the 

 work done by previous chemists on the subject may not be out of place. 

 The following list includes all the salts known at present. 



Cuprous Sodium thiosulphate : — 



(1) 2Cu 2 S 2 3 7Na 2 S 2 3 2 H 2 (Jochum C. C. 1885, 642). 



(2) 2Cu 2 S 2 3 , 7Na 2 S 2 3 12H 2 (Jochum). 



(3) Cu 2 S 2 3 , 3Na 2 S 2 3 2 H 2 (Rammelsberg Pogg. 56, 321). 



(4) Cu 2 S 2 3 3Na 2 S 2 3 6H 2 (Jochum). 



(5) 3 Cu 2 S 2 3 2 Na 2 S 2 3 8 H 2 ( Yortmann, M. Ch. 9, 165). 



(6) 3 Cu 2 S 2 3 2 Na 2 S 2 3 5 H 2 (Lenz. A. 40, 99). 



(7) 5Cu 2 S 2 3 4Na 2 S a 3 8H 2 (Jochum). 



(8) 5Cu 2 S 2 3 4Na 2 S 2 3 6H 2 (Jochum). 



(9) Cu 2 S 2 3 Na 2 S 2 3 H 2 (Russel Ch. Ztg. 9, 233). 



(10) Cu 2 S 2 3 Na 2 S 2 3 3 H 2 (Vortmann M. Ch. 9, 165). 



(11) 5Cu 2 S a 3 3Na 2 S 2 3 2Na,S0 4 H 2 (Jochum). 



