Question

Tlcl3 is more covalent than tlcl why

Answer 1

In TlCl₃, the oxidation state of the Tl is +3 and in case of TlCl, the oxidation state of Tl is +1.
According to the Fajan's rule, covalent character in a given compound depends upon the polarising power of the cation. Higher is the polarising power, higher will be its covalent character.
As, polarising power is directly proportional to the charge present on the cation and inversely proportional to the size of cation, therefore the polarising power of Tl ³⁺ is higher than the Tl⁺¹.
Which means the covalent character of TlCl₃ is higher than TlCl.