Organolead compounds

Thermolysis leads to radical reactions.

Tetraalkyl and tetraaryl lead compounds are inert with respect to attack by air and water at room temperature. WHY ????

Me₃PbCl consists of linear chain
Solid state structure of Cp₂Pb shows polymeric nature, but in the gas phase, discrete Cp₂Pb molecules are present which possess the bent structure similar to silicon analogue. 
R₂Pb=PbR₂ are similar to analogues tin compounds