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Oxygen – Gas and Liquid oxygen

Oxygen atom

Oxygen is an atom formed with 8 protons and 8 neutrons located in his nucleus, surrounded by 8 electrons located on two different shell (2 electrons on the first shell and 6 valence electrons). The atomic number of Oxygen is 8 and the electronic configuration of this atom is 1s2 2s2 2p4 . Most atoms have several naturally occurring isotopes*. Oxygen has three isotopes which are 16O ; 17O and 18O.

*Isotopes : Copies of an atom or element that have the same number of protons but different numbers of neutrons.

Oxygen atom has 6 valence electrons, but 8 electrons are needed to achieve the stability. So a double covalent bond can be formed between two oxygen atoms, they can both be stable by sharing two pairs of electrons.

Oxygen - Gas and Liquid oxygen
Oxygen molecule

Characteristics of Oxygen

  • Oxygen O₂ is a gas without colour, taste or smell.
  • Boiling point = -183 °C
  • Melting point = -219 °C
  • Liquid Oxygen : light blue
  • Solid Oxygen : dark blue crystals.
Oxygen - Gas and Liquid oxygen
Liquid Oxygen

Liquid oxygen

In the atmospheric pressure, oxygen exists as a gas, but in certain conditions it can be liquid. If the pressure is high enough or the temperature is low enough oxygen can be a liquid or even solid. This can be pretty easily visualized in a graph which is known as a phase diagram.

Oxygen - Gas and Liquid oxygen
Phase diagram of oxygen gas

Different uses and application for liquid Oxygen

What is the purpose of liquefying oxygen ?

Liquid Oxygen is often used in food and medicinal applications.

  • It is used as an Oxidant for liquid fuels in rocket propellant systems.
  • It is Commonly used in the metal industry.
  • Steel and iron producers make heavy use of liquid oxygen.
  • Liquid oxygen is used in the pharmaceutical and petroleum industry to manufacture products such as alcohols and aldehydes.
  • It is used as a bleaching and oxidizing agent in the pulp and paper Industry.
  • In the glass, iron, copper, gold, zinc and cement sectors Oxygen improves the combustion phase.
  • Wastewater treatment plants effectively use oxygen to improve the performance of their processes, when the atmosphere is oxygenated fish farmers see improvements in the health and the size of animals.