PbCl4 exist, but PbBr4 and PbI4 do not because of

(1) PbBr4 , PbI4 is unstable compounds and can't exist in natureReason:   Iodine, Bromine are less Electronegative  hence. they can't activate (excite) the 'S' electrons present in the valence sell(i.e Inert pair effect) and they can't oxidize the Pb+2 to Pb+4(2) PbF4 , PbCl4 are exist in natureReason : Fluorine , Chlorine are more Electronegative hence They can activate (excite) the 'S' electrons present in the valence selland oxidize the Pb+2 to Pb+4