SULPIIURETS. 



^7. Sulphurct of antimony. This sulplmret Antimony, 

 is easily formed by heating antimony and sul- 

 phur mixed together in a close vessel ; but it 

 exists native in abundance, being the common 

 ore of antimony. It has the metallic lustre, a 

 leaden grey colour, and is crystallized. The 

 primary form of the crystals is a right rhombic 

 prism, with angles of 88 30', and 91 30'. Its 

 constituents are 



1 atom antimony 5-5 



1 atom sulphur . 2 



7-5 



28. Sulplmret of chromium. I have made no Chromium, 

 experiments on this sulphuret. JBerzelius states, 

 in his Larbok i Kemien,* that it may be formed 

 by passing a current of the vapour of bisulphuret 

 of carbon over protoxide of chromium, raised to 

 a white heat in a porcelain tube. Its colour is 

 light grey, without any metallic lustre j and 

 when pounded in a mortar, it gives a black pow- 

 der. When treated with nitric acid, it may be 

 converted into neutral sulphate of chromium. 

 Hence its constituents are 



1 atom chromium . 3-5 

 1 atom sulphur , 2 



5-5 



* II. . !<;.,. 



