Neon

Neon (chemical symbol: Ne) is a chemical element with atomic number 10. It belongs to the group of noble gases, meaning its atoms do not readily combine with other elements, because its outermost electron shell is full. In its standard state it is an inert, colorless, and odorless gas.

Neon is present in Earth's atmosphere, but in extremely small quantities. It is extracted when air is subjected to intense cooling (fractional distillation of liquid air), since each component of air has a different condensation point. Its most common use is in gas tubes for lighting, which emit a red-orange light when electric current passes through them.

Physical and chemical properties

Neon is a light gas, heavier than helium but lighter than air. Its melting point and boiling point are very low, approaching absolute zero. Because the forces between its atoms are extremely weak, it readily becomes a gas. Chemically, it has no stable compound in common use; compounds have only been created under special, artificial conditions.

Neon light

When neon fills a glass tube through which electric current passes, the electrons of the atoms gain energy and then release light. The color emitted is red-orange. Tubes called 'neon signs' often contain other gases such as argon or xenon, or the tube is coated with phosphor to produce other colors. For this reason the term 'neon' is applied to any such tube, not only to those containing pure neon.

Uses and extraction

Apart from lighting, liquid neon is used in cooling systems with very low temperatures, such as certain lasers and scientific equipment. It is also used in some laser systems and instruments for measuring radiation. Neon cannot be continuously produced on Earth; existing supplies are extracted from air, making its cost dependent on the energy required to separate it from air.