Messrs. F. and E. Rodgers on certain Metallic Cyanurets. 95 



cyanuret are similar to those already described. The cyanuret 

 of sodium is separated from the undecomposed carbonate of 

 soda by treating the white residuum with boiling rectified 

 spirit, and may be obtained in crystals from the solution. It 

 is not very soluble in alcohol. The carbonates of lime, baryta 

 and strontia cannot be decomposed by the bicyanuret of mer- 

 cury at a red heat. The bicyanuret is decomposed by heat, 

 as usual, with the evolution of cyanogen ; but the carbonate 

 does not undergo any change. 



4. Cyanuret of potassium maybe prepared by exposing a 

 mixture of anhydrous carbonate of potash and anhydrous 

 ferrocyanuret of potassium to a moderate red heat, in a covered 

 porcelain crucible, for about twenty minutes. When the cruci- 

 ble is quite cold, a dark mass is seen, which adheres rather 

 firmly to the bottom; on treating this dark mass with hot al- 

 cohol, a colourless solution of cyanuret of potassium is readily 

 obtained. The aqueous solution produces no change in the 

 solutions of the persalts of iron, but it immediately throws 

 down the orange protocyanuret of iron from the solutions of 

 the protosalts. The proportions employed should be nearly 

 one equivalent of anhydrous carbonate of potash to one equi- 

 valent of the anhydrous ferrocyanuret of potassium. The 

 process is very productive, for the weight of the cyanuret of 

 potassium obtained by this process is much greater than the 

 weight of the cyanuret obtained by heating ferrocyanuret of 

 potassium alone, owing to the cyanogen of the cyanuret of 

 iron uniting with the potassium contained in the carbonate of 

 potash ; and moreover the process occupies less time. Some 

 carburet of iron always remains in the crucible. 



5. Cyanuret of potassium may be obtained by heating a 

 mixture of anhydrous carbonate of potash and pure Prussian 

 blue to redness in covered crucibles. It appears that ferro- 

 cyanuret of potassium is generated, and that the cyanuret of 

 potassium results from the subsequent decomposition of this 

 salt The proportion should be about 2*2 grains of pure 

 Prussian blue, and 315 grains of anhydrous carbonate of 

 potash. The cyanuret of potassium may be separated by 

 means of alcohol from the undecomposed carbonate of potash. 

 After the cyanuret of potassium has been dissolved by alcohol, 

 and the undecomposed carbonate of potash by water, the black 

 residue dissolves with effervescence in dilute muriatic acid. 

 The gas generated during the solution has a most offensive 

 odour. 



Ci/aiiurct of sodium may be obtained by an analogous pro- 

 cess, substituting 243 grains of anhydrous carbonate of soda 

 for 315 grains oi carbonate of potash. The same changes occur 



