ON AMMONIACAL PLATINUM B A SES. 47 



Found Experiment 



Platinum 52,95 52,92 



Chlorine 37,96 37, '.a 



Chloroplatinate of sodium communicates a dark-brown colour to the solution of 

 the nitrate; yellow microscopical scales of a rhombic shape are soon deposited, mixed 

 with others of a dark colour. The product seems to be the chloride of platinseraidi- 

 aramine, formed by reduction of the chloroplatinate. 



Xitrous acid (prepared from starch and nitric acid) led through the solution of 

 the nitrate produces a dark-blue colour and a white precipitate of heavy microscopical 

 crystals (short four- or six-sided prisms with obliquely truncated ends). The compound 

 \v;is dissolved in boiling water and, by cooling, the solution stiffened into long stellated 

 needles of the nitrite of platosemidiammine Pt< ^ 3 



Hijdrochloric acid gives yellow needles of the chloride of platosemidiammine with 

 the solution of the nitrate. 



Ferric chloride produces a precipitate of the mixed chlorides of platosemidiam- 

 mine and platinsemidiammine. With ferricyanide of potassium the solution gave the 

 well-known reaction for ferrous salts. 



Ferrocyanide of potassium gives a dirty green uncrystalline precipitate; ferricya- 

 nide of potassium colours the solution of the nitrate intensely blood-red, and produces 

 a brownish uncrystalline precipitate. 



Chromate and bichromate of potassium give brown crystalline precipitates. 



Bisodic orthophosphate in the solution of the nitrate first produces an opalescence, 

 and afterwards a dirty whitish or bluish precipitate is thrown down. 



8. Nitrite, R0 2 . 2NO, was prepared partly by the action of nitrous acid (evol- 

 ved from nitric acid and starch) upon a solution of the nitrate (7), and partly by boi- 

 ling the chloride of platosemidiammine with a solution of nitrite of potassium. The 

 nitrite, which is very sliglitly soluble in cold water, crystallises from a boiling solution, 

 by cooling, into long and fine voluminous prisms of a whitish-yellow colour. When 

 heated it is decomposed with violence and leaves very voluminous platinum. 



Analysis: the nitrite dried at 100°. 



a. 0,3030 gr. gave 0, 1855 gr. metallic platinum. 



b. 0,3055 gr. gave 0,oeoo gr. water = 0,ooo7 gr. hy drogen. 



c. 0,2825 gr. gave 29,3 C. C. nitrogen (temp. of the water 17° Bar. 784 m. m. t 

 18°) =0,0468 gr. nitrogen. 



The formula requires: 



Theory Experiment 



Platinum 197,88—61,09 61,22 (a) 



Nitrogen 56, oo — 17,29 16,58 (c) 



Hydrogen 6, no — 1,85 2,19 (b) 



Oxygen 64,oo — 19,77 20,oi (loss) 



323,88 100,oo 100,oo 



