Is O2 Polar or Nonpolar?

Answer: O2 is a nonpolar molecule due to the linear structure containing two identical molecules with the same electronegativity. Therefore no permanent dipole is induced in any part of the structure. 

Oxygen has rich and storied history in its discovery although ultimately its properties of combustion led to these revelations. This was due to oxygen's high electronegativity (3.44). However O2 in its pure form is small and nonpolar. As a result it has a quite low melting point of -219˚C and boiling point of -183˚C. This means that the compound is a gas at standard temperature and pressure. The atmosphere consists of approximately 21% O2.

To learn more about the lewis dot structure for oxygen, feel free to read this post. This article also discusses the importance of the oxygen revolution and the importance of oxygen within carbon cycling. 

O2 Ball and Stick Diagram
O2 Ball and Stick Diagram. Created with MolView.
How is O2 utilized in the real world?

There is an incredible variety in the functions of oxygen but its inarguably most important role is within biological organisms. Oxygen serves as the final electron acceptor in the electron transport chain and an important byproduct of photosynthesis. This permits the existence of complex life forms such as humans. This is why it makes sense that oxygen therapy is important in medical treatments. It also finds similar utilizations in low-pressure space suits for astronauts. Within industry the most common usage is in smelting iron ore to steel. It is also used in manufacturing of antifreeze, fabrics and plastics. More niche applications include welding, rocket fuel oxidation, and water treatment.