How to find primary valency in coordination compound?
Answers
According to Werner's theory, metal ions have two types of valency-primary and secondary, where the primary valency is said to be satisfied by negative ions only, and the secondary valency can be satisfied by positive ligand, negative or neutral molecule.
examples:- Primary valency is basically the oxidation state of the metal ion forming the complex and most metals basically have positive charge, so it has to balanced by anions.
In K4[Fe(CN)6], the ions are K+ and [Fe(CN)6]4-
Primary valency=2+
Answer:
Primary valency: is nothing but oxidation number of a compound, in a compound WE ALWAYS FIND PRIMARY VALENCE OF METAL.
Now to lets find primary valency of with some examples:
Given: valency of NH3=0 , CO3=-2 , Cl=-1 , CN= -1 , K =1
Ex.1 : K2 [ Ni (CN)4 ]
Here let primary valence i.e valency of Ni (metal) be x
Valency of K is 1 so valency of (K2) = 2 x 1
Valency of CN is -1 so valency of (CN4) = 4 x -1
Now since sum of all the valencies is always 0 i.e
x + 2(1) + 4(-1) = 0
x = + 2
Primary valence is +2
Ex.2 [ Cr (NH3)4 Cl2 ] Cl
Here let primary valence i.e valency of Cr(metal) be x
Valency of Nh3 is 0 so valency of (NH3)4 = 4 x 0
Valency of Cl is -1 so valency of (Cl2) = 2 x -1
Valency of Cl = -1
Now since sum of all the valencies is always 0 i.e
x + 4(0) + 2(-1) + (-1) = 0
x = + 3
Primary valence is +3