A Little More about Allotropes

If you think you’re a good multitasker, you don’t know allotropes. These fascinating compounds can exist in different forms at the same physical state.

History

Allotropes get their name from the ancient Greek words “allos”, which means “other”, and “tropos”, which means form. And they are very aptly named, for they can indeed exist in two forms. Allotrophy is the fascinating quality where some chemical elements can exist in more than one formulation at the same physical state. The different types of states include solid, liquid, gas, and plasma. They achieve this phenomenon by arranging their atoms in different patterns and formulations.

Allotropism was first proposed by Swedish scientist Jons Jakob Berzelius in 1841. Some in the scientific community like to use terms related to the word “polymorphism” because this label is already applied to non-element substances (like compounds) that can exist in two forms in the same phase. However, most chemists and chemistry textbooks use allotropism and its varieties to describe chemical elements that display this remarkable ability.

Examples

Processes like the CVD growth of graphene produce an interesting variety of allotrope. Carbon is the key element, and some of its allotropes include diamond, graphene, graphite, and fullerenes. The differences carbon exhibits at these different states is quite remarkable. Graphite is soft and easily manipulated, while diamond is almost impenetrable.

Phosphorus is another example of an allotrope that displays unique qualities in its varying forms, by way of color. Varieties of this element display as red, white, black, or violet. Oxygen, sulfur, and selenium are some more allotropes. Iron, cobalt, silicon, boron, and arsenic are more examples as well. 

Applications

The applications of allotropes are as wide and varied as their own materials and possibilities are. Tin is used in manufacturing, food storage, and automobiles, and its alter-ego stanene is a 2D topological insulator. Diamonds are used in jewelry and coated on saw blades, and graphite is used in pencils. These amazing elements and their many splendid forms continue to improve lives and make up the foundation of most objects and elements humans depend upon every day.

Now, as you read about the CVD growth of graphene, wear a diamond ring, open a tin can, or write a letter with a pencil you can take a moment and appreciate the remarkable properties these essential and fascinating allotrophic elements provide. As technology and scientific research continue to press on, the implications and applications of allotropes remain promising.