ON AMMONIÅCAL PLATINUM BASES. 51 



H 7 2 2S0 2 + 2(NH 4 .O.S0 2 )+PtNH 3 Cl+HO. I consider it more probable that this for- 

 mula ought to be written atoraically in the following manner: 



^p t JNH 3 "NH 3 j0 ( g 0)2 _ 0s _ 3N H 4 j + pj 2 Q 



I have not examined this sulphite. 



13. Sulphite of ammonium and platosemidiammine, RJ ' ' 4 3NH , was obtained by 

 dissolving the chloride of platosemidiammine in an excess of sulphite of ammonium. 

 The chloride is easily dissolved by the sulphite into a colourless fluid, and when alco- 

 hol is added to this solution, oil-like dröps are thrown down to the bottom of the 

 vessel. They are soon solidified to a white crystalline mäss. The compound was puri- 

 fled by dissolving in water and precipitation with alcohol. The amraonio-sulphite is 

 soluble in water with great facility and crystallises in small colourless four-sided needles. 



The solution of the compound precipitates salts of barium and silver, its ammo- 

 nium being exchanged for equivalent qvantities of barium or silver. If chloride of co- 

 balt is added to the solution, no precipitate is obtained, but by the addition of alco- 

 hol a rose-coloured, curdy matter is thrown down. It is easily soluble in water and 

 the solution yields by evaporation a transparent, rose-coloured, gum-like mäss. 



\o 



Analysis of the ammonio-sulphite of platosemidiammine, dried at 100 c 



1. 0, 1890 gr. gave 0, 1810 gr. metallic platinum and 0,6580 gr. sulphate of barium 

 = 0,0904 gr. sulphur. 



2. 0,fi480 gr. gave 0,2410 gr. platinum and 0,8500 gr. sulphate of barium or 0,1167 

 gr. sulphur. 



The formula requires: 



Calculated Found 



1 3 



Platinum 197,88 — 36,38 37,oi 37, 19 



Sulphur 96,oo — 17,65 18,48 18,oi 



Nitrogen 84,oo 



Hydrogen 2 2, no 



Oxygen 144,oo 



543,88 



14. Sulphite of silver and platosemidiammine, Rj 0(s0 '|0 4 . 2Ag 2 , is thrown down as 



a white curdy precipitate when the ammonio-sulphite (N:o 13) and nitrate of silver 

 are mixed together. 



Analysis; the silver-sulphite dried at 100°. 



a. 0,5460 gr. gave 0,3900 gr. silver and platinum, 0,4350 sulphate of barium — 0,0507 

 gr. sulphur. From the mixture of silver and platinum were obtained 0,3395 

 gr. chloride of silver =0,2556 gr. silver. 



b. 0,'.i3o gr. were moistened with sulphuric acid and ignited. The remaining mix- 

 ture of platinum and sulphate of silver weighed 0,2875 gr. It was then boiled 



