y 
ON CHEMICAL NOMENCLATURE. 263 
The following list will show the application of the ic and ous nomen- 
slature to salts and salifiable oxides :— 
I. List of Salts where Two or more Series of Compounds are formed.} 
Name denoting metallic | Formula of corre- || Name denoting metallic | Formula of corre- 
radical of salt sponding oxide radical of salt sponding oxide 
Cuprous Cu,0 Chromous CrO 
Cupric CuO Chromic Cr,0, 
Mercurous Hg,0 Uranous O, 
Mercuric HgO Uranic ( Uranylic) UO, 
Aurous Au,O Manganous MnO 
Auric Au,O, Manganic Mn,0, 
Thallous T1,0 Ferrous FeO 
Thallic TIO, Ferric Fe,0, 
Stannous SnO Cobaltous CoO 
Stannic Sn0, Cobaltic Co,0, 
Cerous Ce,0, Platinous PtO 
Ceric CeO, | Platinic PtO, 
Names corresponding with platinous and platinic would be applied to 
the corresponding oxides and salts of the other metals of the platinum 
‘oup—distinguishing, however, the other oxides and salts of this group 
/ numeral or other designations. 
The designations given in this Table to the various higher and 
lower series of salts and salifiable oxides have been employed with almost 
complete uniformity by all chemists who have adopted this system of 
nomenclature. 
As a metal rarely—if ever—forms more than two salifiable oxides, the 
ous and ic terminations generally suffice for purposes of distinction so far 
as the salts of metals are concerned. 
The practice of further employing these terminations in the case of 
acid-forming oxides does not lead to confusion, since these oxides are 
distinguished by the name anhydride (or acid). Thus we have 
CrO Cr.0O3 CrO; 
Chromous oxide. Chromic oxide. Chromic anhydride 
(Chromic acid.) 
| Indifferent oxides have frequently been classified and named by 
regarding them as compounds of salifiable, with acid-forming oxides, 
Cr,0, being termed chromic chromate. For stages lower than ous, the 
prefixes hypo and sub are employed. Custom appears to have restricted 
hypo chiefly to acids and to acid-forming oxides, sub to salifiable and to 
indifferent oxides. 
With regard to the termination ous, the minor question arises, how 
far this termination ought to be written in the forms ious and eous. 
The answer is: as seldom as possible. ‘Cupreous’ has generally given 
way to ‘cuprous’; no one writes ‘chromious’ (although the name of 
the metal is ‘chromium’) ; and there is no reason why such names as 
‘ruthenious’ and ‘iridious’ should not equally be shorn of their super- 
fiuous penultimate syllable. 
A further question, concerning which considerable difference of opinion 
has prevailed, is whether any ous or ic terminations ought to be 
employed in the names of salts of which only one class is known—thus 
magnesic sulphate instead of magnesium sulphate. There is something to 
* Tn this list the term ‘salt’ is taken to include ‘haloid salts,’ but to exclude the 
halogen compounds of those elements whose oxides do not yield oxy-salts with acids. 
