Names of Compounds

Binary compounds

Binary compounds are compounds containing only two elements. If one of the two is a metal (or ammonium), then the suffix - ide, is added to the non-metal atom.

Remember :

NaCl - Sodium chloride

CaO - Calcium oxide

AlN - Aluminium nitride

If atoms of two elements form more than one type of compound, then, the prefix mono, di, tri, tetra, penta, etc. are used, to show the number of atoms in the compound.

Dinitrogen monoxide - N₂O

Mononitrogen monoxide - NO

Dinitrogen trioxide - N₂O₃

Mononitrogen dioxide - NO₂

Dinitrogen Pentoxide - N₂O₅

Ternary compounds

Ternary compounds are compounds, which contain atoms of three elements. If one of them is a metal, it is used first and if oxygen is present along with another non-metal, then the suffix - ate is added to part of the name of the other non-metal.

Example: KClO₃ - Potassium chlorate.

This suffix is used, if it is the only compound formed of the three elements. If there is one more compound formed by the same elements, but with a lesser number of oxygen, then instead of the suffix - ate, suffix - ite is used.

Example: KClO₂ - Potassium chlorite.

If a third compound is formed, with still lesser number of oxygen atoms, then, it is called - hypo chlorite.

Example: KClO - Potassium hypochlorite.

 Remember :

In the case of -AlO₂, -ZnO₂ and -PbO₂, the metals being amphoteric, they behave as non-metals.

Binary acids

All acids contain hydrogen. Binary acids contain only two elements one of which is hydrogen. They are named as Hydro, and then the name of the non-metal with the suffix - ic is added.

Remember :

HCl - Hydrochloric acid

HBr - Hydrobromic acid

Hl - Hydroiodic acid

Non - binary acids

They contain more than 2 kinds of atoms. The term 'hydro' is not used.

Instead, the name is based on the second element in the formula.

Remember :

H₂SO₄ - Sulphuric acid

If the same elements form two acids, then the one containing greater number of oxygen atoms gets the suffix - ic at the end, and the one containing less oxygen atoms gets the suffix - ous.