Element of the Week – Carbon

By Michael Edmonds 14/01/2014


In many respects, elements are the fundamental components of the universe to a chemist. While physicists bombard atoms into progressively smaller particles using progressively larger pieces of equipment, most chemists continue to be fascinated by the myriad of arrangements formed when atoms bond and interact with each other. There are less than 100 naturally occurring elements, however, together they form millions of different compounds each with its own unique properties – some vital for life, others more likely to bring death.

So I’ve decided to blog about a different element each week. And what better element to start with than the one that allows formation of the greatest number and widest variety of different compounds – carbon.

Carbon is the sixth smallest atom, indicated by its atomic number of 6 and its’ atomic symbol is simply C. Unique amongst all the elements in its ability to bond to a wide range of other atoms, including oxygen, sulfur, nitrogen, phosphorus, chlorine, bromine, some metals and also other carbon atoms. This “promiscuous”  bonding, alongside its ability to bond to up to four other atoms means that carbon forms the core structure of many of the millions of compounds in existence, from simple structures such as carbon dioxide, larger compounds such as aspirin (a useful drug) and strychnine (a deadly poison), to the enormous protein and DNA molecules which make up our bodies. Carbon is the most versatile element, and plays a central role in life on Earth which is why science fiction descriptions of human beings as “carbon based life forms” is perfectly reasonable.                                              

Aspirin

 

Note – The adjacent structure  show how atoms are arranged to make up the compound, aspirin. Carbon atoms are represented with the black spheres, oxygen atoms with the red spheres and hydrogen atoms with the white spheres.

 

 

 

In addition to its impressive ability to form a huge variety of compounds with other elements, carbon atoms can assemble into some fascinating structures all by themselves. Diamonds are formed by carbon atoms reinforcing each other in tetrahedral structure resulting is a substance that is both incredibly hard and resilient. Arranged in a less structured fashion carbon forms coal, brittle and black. Where carbon atoms form into flat hexagon structures layered in sheets, we have graphite, the lubricating properties of which come from the ability of these microscopic sheets of carbon to slide over each other. And more recently researchers have prepared unique structures like buckyballs and nanotubes which have been used for a wide range of applications from anti-viral compounds to the construction of nanoscopic machines.

A more detailed description of the different forms of carbon (i.e. carbon allotropes) can be found here.   Carbon is a unique element, its versatility being responsible for life on Earth and probably anywhere else it may exist and it well deserves being the first element discussed in this series.