252 Chemical Nomenclature of Berzelius. 
ticles sub or super, are prefixed to the name derived from the elec- 
tro-negative body, as when we say subowide, superonide. Wemay 
also use terms of this kind, sulphuret of copper, oxide of iron, which 
express the nature of the components of substances, without refer- 
ence to the proportions in which they are combined. _ 
The electro-negative compounds formed by oxygen have always 
been distinguished from the electro-positive, formed by the same ele- 
ment in the nomenclature of de Morveau, although no reference 
was had to such a theoretical distinction. The first class were call- 
ed acids, the second oxides. In these names and their terminations, 
there is a deviation from the rule laid down above, which usage has 
sanctioned.(4) This marked distinction in nomenclature between the 
electro-negative and electro-positive compounds is very convenient, 
and I propose to extend it to all binary compounds.—I shall, there- 
fore, call those combinations of sulphur, selenium, tellurium, chlo- 
rine, bromine, iodine, and fluorine, with bodies less electro-negative 
than themselves, which in their atomic constitution correspond to the 
acids,(5) by the names sulphides, selenides, tellurides, chlorides, bro- 
mides, rodides, and. fluorides: while those combinations of the same 
bodies with the electro-positive metals, which in the atomie rela- 
tions of the components correspond to the bases, I shall term, sul- 
phurets, seleniurets, tellurets, chlorurets, bromurets, todurets, and fluo- 
rurets.(6) The same rule should be followed in those combinations 
(4) In a perfect nomenclature, according to the system of Berzelius, the oxides 
awould have the name orurets, and the acids would be called oxides. Reference is 
made in this paragraph to such a eonsequence of the rule of nomenclature.— Trans. 
(5) The object of a reference to the atomic relations of the components is devel- 
oped in the following paragraph, taken from the author’s general remarks upon the 
compounds of the metals with sulphur. (Vol. II, p. 252.) ‘*The combinations 6f 
sulphur with the electro-positive metals are called swlphwrets or sulphobases. Those 
with the electro-negative metals are called sulphides, either when their composition 
is proportional to that of an acid compound of the metal with oxygen, or when they 
are capable of combining with sulphobases.”— Trans. 
(6) Oxygen, sulphur and tellurium “unite with electro-negative combustibles, 
forming electro-negative compounds, similar in certain particulars to acids, and with 
electro-positive combustibles, forming electro-positive compounds, analogous to the 
bases. These compounds can neutralize each other, just as the oxides neutralize 
the acids, and thus they produce salts.” (Vol. I, p. 220.) ae 
“We have said, in treating of oxygen, that sulphur forms combinations which are 
analogous to acids, and others analogous to buses. The electro-negative compounds © 
are called sulphides, the electro-positive sulphurets or sulphobases.” (Vol. I, p. 253.) 
«The combinations of the electro-positive metals with selenium are called sele- 
niurets or seleni-bases, those of the electro-negative metals are called selenides. 
These latter unite with the former, producing salts.” (Vol. II, p. 420.)—Zrans. 
