Name: Oxygen



Symbol: O



Atomic Number: 8



Atomic Mass: 15.9994 amu



Melting Point: -218.4 °C (54.750008 K, -361.12 °F)



Boiling Point: -183.0 °C (90.15 K, -297.4 °F)



CAS (chemical abstract number) 7782-44-7



Valence 2



Molecular Weight 15.9994(3) amu



Oxidation State -2



Orbital Electrons [He]2S2 2P4



Boiling Point -182.97 C



Melting Point -218.40 C



Density (gas) @ OC 1.429 g/L



Density (liquid) -183 C 1.14 g/L



Molar Volume 17.36x10-6 m3/mol



Heat of Vaporisation 3.4099 kj/mol



Heat of Fusion 0.22259 kj/mol



Specific Heat Capacity 920 J/(kg.K)



Paramagnetism strong



Atomic Radii 0.66 Å



Ionic Radii (crystal) 1.26 Å



van de Waals Radii 1.52 Å



Electronegativity 3.44 (Pauling)



Electrical Conductivity 0.02674 W/(m.K)



Crystal Structure cubic



Origin of Name oxy genes = "acid forming" [Greek]







Oxygen was discovered for the first time by a Swedish Chemist, Carl Wilhelm Scheele, in 1772. Joseph Priestly, an English chemist, independently, discovered oxygen in 1774 and published his findings the same year, three years before Scheele published. Antonie Lavoisier, a French chemist, also discovered oxygen in 1775, was the first to recognize it as an element, and coined its name "oxygen" - which comes from a Greek word that means "acid-former"




Oxygen, the second-largest volume industrial gas, is produced commercially as a gas or as a liquid by several methods. These include:

1.Cryogenic Air separation, a process that compresses and cools atmospheric air, then, - relying on different boiling points - separates the resulting liquid into its components in a distillation column.

2.Vacuum Pressure Swing Adsorption (VPSA), a non-cryogenic technology that produces oxygen from air by using an adsorbent in a pressure swing process to remove nitrogen.