276 Sulphite of the Protoxide of Platinum and Soda. 



to a red heat. The residue, which consisted of platinum and 

 the chloride of sodium, was washed with water, and to this 

 water sulphuric acid was added, in order to determine the soda 

 by weighing the sulphate of soda thus formed. In order to de- 

 termine the quantity of sulphurous acid, a weighed portion of 

 the salt was put into water and through this chlorine conducted. 

 From this, the sulphuric acid which was thus formed, was pre- 

 cipitated by the chloride of barium. Of the salt dried at 200°, 

 (Centigrade,) 



1. 1.850 grammes, gave 1.190 sulphate of soda, which is 

 equivalent to 0.521 soda; and 0.543 platinum, equivalent to 

 0.587 protoxide of platinum. 



2. 1.108 grammes, gave 0.328 platinum, =0.3546 protoxide of 

 platinum. 



3. 1.488 grammes, gave 0.954 sulphate of soda, =0.418 soda. 



4. 0.867 grammes, gave 1.234 sulphate of baryta, =0.3395 

 sulphurous acid. 



5. 0.874 grammes, gave 1.249 sulphate of baryta, =0.3436 

 sulphurous acid. 



These numbers give for the composition of the salt the follow- 

 ing formula: 3NaOS0 2 +PtOSO : 

 parts, are contained, 



Calculated. 



Soda, 28.53 



Protoxide of pla- > _,_ , . 

 r S- 32.44 

 tinum, 5 



Sulphurous acid, 39.03 39.16 39.32 



The salt when dried by 100°, (Centigrade,) lost, when heated 

 up to the temperature 200°, according to three different experi- 

 ments, 3.90, 4.28, 4.16 per cent, of water. This gives for the 

 formula of the salt, containing water, 2(3NaOS0 2 +PtOS0 3 )-}- 

 3HO, according to which formula, the quantity of water reck- 

 oned amounts to 3.94 per cent. If protoxide of platinum is sus- 

 pended in water, and sulphurous acid conducted through it, the 

 former, although with difficulty, is gradually dissolved with 

 a green brownish color, and out of this solution the above de- 

 scribed salt can be precipitated by the carbonate of soda. 



When this double sulphite is dissolved in only so much diluted 

 sulphuric or hydrochloric acid as is requisite to its solution, and 

 the fluid by a low temperature evaporated, a yellow powder falls 

 down, in proportion as the sulphurous acid escapes, which is also 



