For which property of carbon atom it had been possible for formation of several lakhs of organic compound
Carbon atoms are very small, and therefore form very strong bonds, particularly with themselves. Carbon has the ability to 'catonate', forming long chains of carbon-carbon bonds, which theoretically can have an infinite number of carbons in them. The diversity of organic compounds is due to this ability - carbon may form single ('sigma') bonds, double ('pi') bonds, even triple bonds...and of course it can bond with many other elements like nitrogen (in amides), oxygen (in alcohols), halogens (in haloalkanes) and of course hydrogen. Unlike silicon, which can bond to about 3-4 other silicon naturally, carbon has the inert ability to continuously bind with other carbon molecules. The more carbons that carbon binds to, the more isomers there are. Because of this, the number of compounds increases dramatically as the number of carbons within an organic compound grows. And this is just based on carbon only compounds. When functional groups are brought into the picture, the amount of compounds that can be created are near endless.