100 CH^'MK/AL "NO^^ChAYURE AND NOTATION. 



: coitipGtin(i. l 'aiid h'as a .'iermiiiafitta expressive of combination 

 attached to it. Thus a compound of chlorine and phosphorus 

 is called chloride of phosphorus, and not phosphuret of chlo- 

 rine; of sulphur and carbon,, sulphuret of carbon, and not car- 

 buret of sulphur. The combinations of metallic elements 

 among themselves are distinguished by the general term alloys, 

 and those of mercury as amalgams. 



(b) The binary compounds of oxygen which possess acid 

 properties, are named on a different principle. Thus the acid 

 compound of titanium and oxygen is called titanic acid; of 

 chromium and oxygen, chromic acid ; or the name of the acid is 

 derived from that of the substance in combination with oxygen, 

 with the termination ic. Where the same element was known 

 to form two acid compounds with oxygen, the termination ous 

 was applied to that which contained the least proportion of 

 oxygen, as in sulphurous and sulphuric acids. On the dis- 

 covery of an acid compound of sulphur which contained less 

 oxygen than that already named sulphurous acid, it was called 

 hyposulphurous acid, (from the Greek vvo, under) and another 

 new compound, intermediate between the sulphurous and sul- 

 phuric acids, was named hyposulphuric acid. On the same princi- 

 ple, an acid containing a greater proportion of oxygen than that 

 already named chloric acid was named hyperchloric acid, (from 

 the Greek vnep, over). The names of the different acid com- 

 pounds of oxygen and sulphur, which have been referred to 

 for illustration, with the relative proportions of oxygen which 

 they contain, are as foUows : 



Composition. 



Names. Sulphur. Oxygen. 



Hyposulphurous acid 100 49.75 



Sulphurous acid 100 99.50 



Hyposulphuric acid 100 124..>7 



Sulphuric acid 100 149.25 



This system has been adopted for all analogous acids. An 

 acid of chlorine, containing more oxygen than chloric acid, is 

 named hyperchloric acid, and other similar compounds, which 

 all contain an unusually large proportion of oxygen are dis- 

 tinguished in the same manner, as hyperiodic acid and hyper- 

 manganic acid. The hyperchloric acid is also sometimes called 

 perchloric and oxichloric ; but these last terms do not seem so 

 suitable as the first. 



