Which form is an example of a sulfur allotrope?

• A. Diamond
• B. Graphite
• C. Rhombic sulfur
• D. Ozone

Answer: (C)

Allotropy means an element can exist in more than one structural form, leading to different arrangements of the same atoms and distinct properties. Sulfur has several solid forms based on different arrangements of S atoms, with rhombic sulfur being the orthorhombic form composed of S8 rings that pack into a rhombic lattice and remain stable at room temperature as yellow crystals. This makes it a true sulfur allotrope.

The other items aren’t sulfur: diamond and graphite are forms of carbon, and ozone is a different form of oxygen.