Primary ValencyPrimary valencies are those which a metal exhibits in the formation of simple salts. e.g. CoCl3 , NaCl, CuSO4 etc.In modern terminology it represents the oxidation number of metal.e.g. the primary valencies of Co in CoCl3 is 3,  and oxidation state +3 Similarly, for NaCl, oxidation state of Na is +1, for CuSO4, oxidation state of Cu is +2The primary valencies are ionizable.These are written outside the coordination sphere.These are non-directional and do not give any geometry to compl

Primary valency refers to the oxidation state of a metal in a compound, which is determined by the number of ions it can donate or accept. This is often seen in the formation of simple salts. For example, in CoCl3, the primary valency of Co (Cobalt) is 3, indicating an oxidation state of +3. This means that Cobalt can donate 3 electrons. Similarly, in NaCl, the primary valency of Na (Sodium) is 1, indicating an oxidation state of +1. In CuSO4, the primary valency of Cu (Copper) is 2, indicating an oxidation state of +2.

Primary valencies are ionizable, meaning they can form ions. They are written outside the coordination sphere in a chemical formula. They are non-directional, meaning they do not influence the geometric shape of the compound.