Neon
Chemistry
Neon is the first p-block noble gas, and the first element with a true octet of electrons. It is inert: as is the case with its lighter analogue, helium, no strongly bound neutral molecules containing neon have been identified. The ions [NeAr]+, [NeH]+, and [HeNe]+ have been observed from optical and mass spectrometric studies. Solid neon clathrate hydrate was produced from water ice and neon gas at pressures 0.35–0.48 GPa and temperatures about −30 °C. Ne atoms are not bonded to water and can freely move through this material. They can be extracted by placing the clathrate into a vacuum chamber for several days, yielding ice XVI, the least dense crystalline form of water.
Neon-21