Lonsdaleite, chaoite, and schwarzite are all unusual variant forms of a single chemical element. Which one?
A) Aluminum B) Calcium C) Carbon ü D) Sulfur
Carbon comes in many forms, from soft graphite to hard diamond. The differences amongst them result from the different geometrical arrangements of the carbon atoms. In each of the three forms mentioned, the underlying arrangement is hexagonal. Lonsdaleite is similar to diamond, but with hexagonal rather than cubic crystals. Chaoite is produced in meteorite impacts. In schwarzite, the presence of heptagonal (seven-sided) crystals distorts the hexagonal layers.
