Question

In $[Fe{({H_2}O)_6}]C{l_3}$ , six ${H_2}O$ are joined by primary valency and three $Cl$ are joined by secondary valency.
If true enter $1$ , else enter $0$ .

Answer 1

Primary valency in coordination complexes is the number of negative ions which are equal to the charge on a metal ion. Primary valencies are ionisable. And secondary valencies in coordination complexes are satisfied by the ligands which are equal to the coordination number of complexes.

Complete Answer:
According to Werner's theory of coordination compounds, one of the postulates states that the coordination compound shows two types of valencies named as primary valency and secondary valency.
Primary valency is the number of negative ions attached to the complex in order to neutral the charge. It is equal to the charge on the metal ion. On the other hand, secondary valencies are the number of molecules that are attached to metal ions or can say that are coordinated to metal ions. In coordination chemistry, the molecules or ions which are attached to metal are called ligands. Secondary valency of coordination complex is equal to its coordination number.
In case of $[Fe{({H_2}O)_6}]C{l_3}$ ,
In this compound, the coordination number of iron is $6$ and water molecules that are ${H_2}O$ satisfy all the six secondary valencies. And chloride ions that are $C{l^ - }$ ions satisfy the three primary valencies. These valencies are non-direction in character.

Hence, $0$ is correct.

Note:
The primary valency is generally the oxidation state of metal atom while secondary valency is the coordination number of coordination complex. Primary valencies are ionisable and satisfied by negative ions and secondary valencies are non-ionisable and satisfied by neutral molecules or negative ions. The secondary valency is always fixed for every metal atom that is the coordination number is fixed for every metal atom. The central atom surrounded by the number of ligands is responsible for the shape of the complex.