Oxosalts

Oxosalts are salts whose anions derive from oxoacids (acids that contain oxygen) after the acidic hydrogen atoms are removed.

Traditional nomenclature

In traditional (common) nomenclature the oxoacid ending -ic becomes -ate and -ous becomes -ite when forming the salt name. The metal name is stated first; indicate the metal oxidation state using Roman numerals when necessary.

Examples:

  • Na₂SO₄: sodium sulfate (from H₂SO₄, sulfuric acid)
  • KNO₃: potassium nitrate (from HNO₃, nitric acid)
  • CaCO₃: calcium carbonate (from H₂CO₃, carbonic acid)
  • NaClO₄: sodium perchlorate (from HClO₄, perchloric acid)
  • KClO₃: potassium chlorate (from HClO₃, chloric acid)
  • Fe₂(SO₄)₃: iron(III) sulfate (from H₂SO₄, sulfuric acid)
  • KMnO₄: potassium permanganate (from HMnO₄, permanganic acid)

Additive (systematic) nomenclature

Additive systematic names use prefixes to indicate the number or type of oxygen-containing groups in the anion (mono-, di-, tri-, tetra-, etc.), and name the anionic unit followed by the metal (and multiplicity if needed).

Examples:

  • KNO₃: trioxonitrate of potassium
  • CaSO₄: tetraoxosulfate of calcium
  • NaClO: oxochlorate of sodium
  • Ca(ClO)₂: bis(oxochlorate) of calcium
  • Fe₂(SO₄)₃: tris(tetraoxosulfate) of diiron
  • AgNO₃: trioxonitrate of silver

Compositional systematic nomenclature

Compositional names indicate the number of oxygen atoms and the overall charge of the anion (e.g., trioxonitrate(1-)), followed by the metal and its oxidation state when appropriate.

Examples:

  • KNO₃: trioxonitrate(1-) of potassium
  • CaSO₄: tetraoxosulfate(4+) of calcium
  • NaClO: monoxochlorate(1-) of sodium
  • Ca(ClO)₂: dioxochlorate(1-) of calcium
  • Fe₂(SO₄)₃: tris(tetraoxosulfate)(2-) of iron(2+)
  • CuNO₃: trioxonitrate(1-) of copper

Common oxosalts

  • CaCO₃ (calcium carbonate): main component of limestone and marble.
  • CaSO₄ (calcium sulfate): gypsum, used in plasters and construction.
  • KNO₃ (potassium nitrate): used in fertilizers and food preservation.
  • KMnO₄ (potassium permanganate): oxidizing agent and disinfectant.
  • NaClO (sodium hypochlorite): common bleach and disinfectant.

1. Indicate the name of the ion: (8 points)

a ) CO₃²⁻

b ) SO₄²⁻

c ) NO₃⁻

d ) ClO₃⁻

e ) ClO₄⁻

f ) PO₄³⁻

g ) MnO₄⁻

2. Name using traditional nomenclature: (12 points)

a ) Na₂CO₃

b ) K₂SO₄

c ) AgNO₃

d ) Ca(ClO)₂

e ) NaClO₄

f ) KMnO₄

g ) Na₂SO₄

h ) KClO₃

i ) CaCO₃

j ) NaNO₂

k ) NaClO

l ) NaClO₂

3. Write the formulas for the following compounds: (12 points)

a ) Barium sulfate

b ) Sodium sulfite

c ) Potassium nitrate

d ) Calcium carbonate

e ) Magnesium perchlorate

f ) Aluminum phosphate

g ) Potassium permanganate

h ) Sodium hypochlorite

i ) Silver nitrite

j ) Aluminum sulfate

k ) Calcium chlorate

l ) Potassium chromate

4. Name using compositional systematic nomenclature: (10 points)

a ) Na₂CO₃

b ) CuSO₄

c ) AgNO₃

d ) Ca(ClO)₂

e ) NaClO₄

f ) KMnO₄

g ) NaClO₃

h ) KClO₂

i ) CaSO₃

j ) Na₃PO₄

5. Name using additive systematic nomenclature: (10 points)

a ) Na₂CO₃

b ) CuSO₄

c ) AgNO₃

d ) Ca(ClO)₂

e ) NaClO₄

f ) KMnO₄

g ) NaClO₃

h ) KClO₂

i ) CaSO₃

j ) Na₃PO₄

6. Write the formulas for the following compounds (compositional names): (10 points)

a ) Barium tetraoxosulfate(2-)

b ) Disodium trioxosulfate

c ) Potassium trioxonitrate(1-)

d ) Calcium trioxocarbonate

e ) Magnesium tetraoxochlorate(1-)

f ) Aluminum tetraoxophosphate

g ) Potassium tetraoxomanganate(1-)

h ) Sodium monoxochlorate

i ) Silver dioxonitrate(1-)

j ) Dipotassium tetraoxochromate