1
The Nomenclature of Compounds
–system of naming compounds
•common and systematic names
1.15 Names of Ions
•Monoatomic cations
–name of the element + ion (Ca2+ →calcium
ion)
–Roman numeral for the charge of the ion, if more
than one charges are possible (Fe2+ →iron(II)
ion, Fe3+ →iron(III) ion)
•Monoatomic anions
–root of element name + -ide + ion (Cl-→
chloride ion, O2-→oxide ion)
•Polyatomic ions -Table 1.3
–oxoanions
•root of element name + -ate + ion (SO42-→sulfate
ion)
•oxoanions with different number of O atoms -hypo-
(per-) + root of element name + -ite (-ate) + ion
(ClO-→hypoclorite, ClO2-→chlorite, ClO3-→
chlorate, ClO4-→perchlorate ion)
–H-containing anions -add “hydrogen” to the
name (H2PO4-dihydrogen phosphate ion)
1.16 Names of Ionic Compounds
•Name of cation + name of anion (MgSO4→
magnesium sulfate, Co2S3→cobalt(III) sulfide)
•Charge balance -Co23+S32-→2x(+3) + 3x(-2) = 0
•Cross rule -Al3+, SO42-→Al2(SO4)3
•Hydrates -ionic compounds containing a definite
proportion of water (CoCl2·6H2O →cobalt(II)
chloride hexahydrate); Greek prefixes -mono-, di-,...)
Examples:
•Give the systematic names of: Na2HPO4,
CuSO4·5H2O, MnBr2, KIO4.
–sodium hydrogen phosphate (Na+ , HPO42-)
–copper(II) sulfate pentahydrate (Cu2+, SO42-)
–manganese(II) bromide (Mn2+, Br-)
–potassium periodate (K+, IO4-)
