CHEMICAL NOMENCLATURE AND NOTATION. -)9 



lead, which contains less oxygejr- taan; th3 oxide distinguished 

 as the protoxide of the same metal. 



The compounds of chlorine and certain other elements are 

 distinguished in the same manner as the oxides. Such elements 

 resemble oxygen in several respects, particularly in the manner 

 in which their compounds are decomposed by electricity. Chlo- 

 rine,, for example, like oxygen, proceeds to the positive pole, 

 and is therefore classed with oxygen as an electro-negative 

 substance, in a division of elements grounded on their electrical 

 relations. Thus with the other elementary bodies, 



Oxygen forms oxides, 



Chlorine chlorides, 



Bromine bromides, 



Iodine iodides, 



Fluorine fluorides, 



Cyanogen cyanides, 



Sulphur sulphurets. 



As cyanogen although a compound body comports itself in its 

 combinations like an electro-negative element, its compounds 

 are named in the same manner as the oxides. When several 

 chlorides of the same metal exist, they are distinguished by the 

 same numerical prefixes as the oxides. Thus we have the 

 protochloride and the deutochloride or perchloride of iron ; the 

 protochloride, and the bichloride of tin ; the application of the 

 prefix hi being more generally sanctioned in the case of chlo- 

 rides than oxides. The compounds of sulphur greatly resemble 

 the oxides, but they are named sulphurets and not sulphides. 

 Berzelius indeed applies the term sulphuret to such binary com- 

 pounds of sulphur only as are basic or correspond with basic ox- 

 ides ; while sulphide is applied to such as are acid, or correspond 

 with acid oxides. Hence, he has the sulphuret of potassium, and 

 the sulphide of arsenic and sulphide of carbon. Compounds of 

 chlorine are distinguished by him into chlorurets and chlorides, 

 on the same principle ; thus he speaks of the chloruret of potas- 

 sium and of the chloride of phosphorus. But these distinctions 

 have not been regarded by French or English chemists. 



Compounds of carbon and phosphorus with electro-positive 

 elements are named carburets and phosphurets, as the carburet 

 of iron, the phosphuret of lead. In all such cases it is the 

 name of the electro-negative element, or that which most 

 resembles oxygen, which is placed first in the name of the 



H 2 



