Why graphite has higher Bond order than diamond? Thanks

The reason behind this is bond energy of C-C bond . In diamond bondlength of C-C bond is 154 pm whereas in graphite it is 145 pm and therefore bond order of graphite is more than diamond that is equal to 1.5 (approx) .  

As u would know that bond length is inversely proportional to bond order . 

  Hope it helps u :) 

Graphite has sp2 hybridised C-C bonds , while Diamond has sp3 hybridised carbon .And sp2 has higher bond order , which means high bond order . 

Graphite has pi character in C-C bond while diamond has only sigma bonds. That is why C-C bond order in graphite is more than that in diamond