Which allotrope of carbon is used in lubricants, sporting goods, and aircraft?

a. graphite

b. diamond

c. fullerene

d. coal

The allotrope of carbon that is used in lubricants, sporting goods, and aircraft is graphite. The answer is letter A. Graphite is a good conductor of heat and is very soft. The layers of lattice of each are bound to the adjacent layers by weak Van der Waals forces which allow the layers to slide over one another easily.