Question

what is the mean of carbon allotropes

Answer 1

carbon allotropes are the various forms in which carbon is present.....
eg: diamond is an allotrope of carbon

Answer 2

When an element exists in more than one crystalline form, those forms are called allotropes; the two most common allotropes of carbon are diamond and graphite.The distance between carbon atoms along the bond is 1.54 × 10−8 cm, and this is called the single-bond length.