ON AMMONIACAL PLATINUM B A SES. 45 



4. Gyanide RCy L . may be prepared by adding a solution of cyanide of potassium 

 to the solution of the nitrate; an excess of the cyanide of potassium must be carefully 

 avoided. If the solutions are concentrated the cyanide of platosemidiammine soon crys- 

 tallises. The crystals mag quickly be separated from the liquid, from which an orange- 

 coloured powder is precipitated. The cyanide crystallises well in colourless needles. 



Analysis: the cyanide dried över sulphuric acid 

 0,3150 gr. gave 0,2200 gr. platinum. 



The formula requires: 



Calculated Found 



Platinum 69,ro 69,84 



The cyanide, by boiling with a solution of nitrate of silver, gives cyanide of sil- 

 ver and a colourless solution, from which, by adding sal ammoniac, the excess of silver 

 is first separated as chloride and afterwards yellow needles of the chloride of plato- 

 semidiammine are formed. 



The orange-coloured powder, which separates after the cyanide, was not analysed. 

 It is easily soluble in cyanide of potassium and yields fluorescent needles of plato- 

 cyanide of potassium. 



The cyanide is isomeric with the cyanide of platosammine and with the plato- 

 cyanide of platodiammine. 



5. Plntocyanide RCy 4 Pt+3H 2 (?) If a solution of platocyanide of potassium is 

 added to the nitrate of platosemidiammine a voluminous, sulphur-coloured, uncrystal- 

 line precipitate is thrown down. The compound in its dry state forms a light-yellow 

 powder, -which, on being heated, is decomposed with a slight detonation. It does not 

 give hydrocyanic acid with sulphuric acid. 



Analysis; the compound dried över sulphuric acid. 



1. 0,1865 gr. gave 0,1270 gr. metallic platinum. 



2. 0,3440 gr. gave 0,0940 carbonic acid = 0,0250 gr. carbon and 0,otio gr. water = 

 0,0066 gr. hydrogen. 



The formula requires: 



Calculated Experiment 



Platinum 67,33 68,ou 



Carbon 8,16 7,44 



Hydrogen 2,04 1,92 



6. SulpJiocyanate, R(CyS),, is obtained by adding sulphocyanate of ammonia to a 

 solution of the nitrate of the base. The compound soon crystallises in flat, shining 

 straw-coloured prisms. When sulphocyanate of potassium in excess was mixed with a 

 solution of the nitrate of platosemidiammine, ammonia was evolved and the solution 

 turned dark-red. By evaporation colourless crystals of nitrate of potassium, and a dark 

 liquid, in all probability containing platosulphocyanate of potassium, were obtained. 



