Blue Oxygen?

As we see the symbol O2, We will definitely know that's OXYGEN. Oxygen has A lot of properties , such as:

• Colourless
• Odourless
• Gas state in room temperature
• Atomic number 8
• A diatomic molecules
• React with metal to form metal oxides
• Can be produced by heating potassium permanganate crystals

But do you know oxygen can be blue in colour? Let's find out!

Liquid Oxygen 

When oxygen reaches its boiling point( 90.20 K /−297.31 °F/ −182.95 °C), Oxygen will change state from gas to liquid. Its properties are:

• Pale blue colour
• Can cause a material become extremely brittle
• Good oxidizing agent
• Density 1.141 g/cm3

In commerce, liquid oxygen is widely used in industrial and medicine. Liquid oxygen is also commonly used as cryogenic liquid oxidizer propellent for spacecraft rocket applications. Some explosive thing in the past had contained liquid oxygen too. Last but not least, it's used to maintain high level of micro-organisms in the waste water treatment for the activated sludge process (treat sewage or industrial waste by using air and composed bacteria and protozoa).

Solid Oxygen

After talking about liquid oxygen, it's solidified time. The freezing point of oxygen is 54.36 K/−218.79 °C/ −361.82 °F. And we all know something pass the freezing point, the thing will become solid, same as oxygen as well. Same as liquid oxygen, solid oxygen also has the same colour, which is pale blue , caused by absorption in red light of the visible light spectrum. Its density ranges from 21 cm3/mol in α-phase to 23 cm3/mol in γ-phase. As I mentioned in the last sentence, you will noticed there are different phase from α-phase to ζ-phase. Here's a list of them.

• α-phase: light blue — forms at 1 atm below 23.8 K
• β-phase: faint blue to pink — forms at 1 atm below 43.8 K
• γ-phase: faint blue — forms at 1 atm below 54.36 K
• δ-phase: orange — forms at room temperature by applying a pressure of  9 GPa
• ε-phase: dark-red to black — forms at room temperature at pressures greater than 10 GPa
• ζ-phase: metallic — forms at pressures greater than 96 GPa

I hope you all enjoy the blue exploration of oxygen. Feel free to leave a comment.