Question

_________, __________ and _____________ are three crystalline forms of carbon.

• A. Diamond, graphite
• B. fullerenes

Answer 1

Allotropy: Allotropy or allotropism is the property of chemical elements to exist in two or more different forms, known as allotropes of these elements. The three crystalline forms of carbon are diamond, graphite, and fullerenes.

• Each $\mathrm{Carbon}\left(\mathrm{C}\right)$ atom is bonded to four other carbon atoms in a diamond, forming a strong structure that makes the diamond very hard.
• In graphite, each $\mathrm{Carbon}\left(\mathrm{C}\right)$ atom is bonded to three other carbon atoms and the atoms forms layers that are only weakly bonded together. This makes graphite soft and slippery.
• In a fullerene, $\mathrm{Carbon}\left(\mathrm{C}\right)$ atoms are bonded to three other atoms in a soccer ball pattern. The bonds are weak, so fullerenes can dissolve and form solutions.

Thus, Diamond, graphite, and fullerenes are three crystalline forms of carbon.