NAMING IONIC COMPOUNDS
Positively charged ions are called cations.
Negatively charged ions are called anions.
The cation is always named first.
CATIONS:
Cations can be metals or polyatomic ions. The ammonium ion (NH4+) is an
example of a polyatomic cation. Hydrogen can also form a cation, H+, in which
case the name hydrogen is used in naming. For metals having only one possible
charge (valency) the name of the metal is used. Examples are Group 1 (1A)
metals (charge +1), Group 2 (IIA) metals (charge 2+), aluminum (charge 3+), zinc
(charge 2+), silver (charge 1+). For metals that can have more than one charge
(valency) the name of the metal is followed by the valelncy in capital Roman
numerals in brackets.
Element
Copper
Copper
Iron
Iron
Lead
Lead
Mercury
Mercury
Tin
Tin
Cation
Cu+
Cu+2
Fe+2
Fe+3
Pb+2
PB+2
Hg+
Hg+2
Sn+2
Sn+4
Preferred Name
Copper (I)
Copper (II)
Iron (II)
Iron (III)
Lead (II)
Lead (IV)
Mercury (I)
Mercury (II)
Tin (II)
Tin (IV)
ANIONS:
Anions can be a negatively charged element or a polyatomic ion. Negatively
charged elements can have the suffix –ide. Examples are oxide (O-2), sulfide (S2), fluoride (F-), chloride (Cl-), bromide (Br-), iodide (I-), nitride (N-), hydride (H-).
A number of polyatomic anions exist, and these include:
SO4-2
sulfate
CO3-2
carbonate
NO3-
nitrate
HCO3-
hydrogen carbonate
PO4-3
phosphate
OH-
hydroxide
Compounds containing ions of elements:
MgO Cation: magnesium
Anion: oxide
Magnesium oxide
FeS
Cation: iron (II)
Anion: sulfide
iron (II) sulfide
LiH
Cation: lithium
Anion: hydride
lithium hydride
H2S
Cation: Hydrogen
Anion: sulfide
hydrogen sulfide
Compounds containing polyatomic ions:
NaOH
Cation: sodium
Anion: hydroxide
sodium hydroxide
CaCO2
Cation: calcium
Anion: carbonate
calcium carbonate
(NH4)2SO4
Cation: ammonium Anion: sulfate
ammonium sulfate