Neon has been shown to crystallize with other substances and form clathrates or Van der Waals solids.
[3] Van der Waals molecules are those where neon is held onto other components by London dispersion forces.
The forces are very weak, so the bonds will be disrupted if there is too much molecular vibration, which happens if the temperature is too high (above that of solid neon).
The dimer Ne2, trimer Ne3 and neon tetramer Ne4 have all been characterised by Coulomb explosion imaging.
The neon trimer is shaped approximately like an equilateral triangle with sides 3.3 Å long.
The neon tetramer takes the form of a tetrahedron with sides around 3.2 Å.
[15] Neon can form a very weak bond to a transition metal atom as a ligand, for example Cr(CO)5Ne,[16] Mo(CO)5Ne, and W(CO)5Ne.
[17] The cyclic molecule Be2O2 can be made by evaporating Be with a laser with oxygen and an excess of inert gas.
It coordinates two noble gas atoms and has had spectra measured in solid neon matrices.
When neon is added to the cyclic molecule, the ∠O-Be-O decreases and the O-Be bond lengths increase.
The isotope 22Ne is strongly enriched in carbonaceous chondrite meteorites, by more than 1,000 times its occurrence on Earth.
The neon atoms become trapped in a cage of five metal triformate units.
[35] Neon causes the zeolite to remain crystalline, otherwise at pressure of 20 GPa it would have collapsed and become amorphous.
[37] When metals are evaporated into a thin gas of hydrogen and neon in a strong electric field, ions are formed that are called neonides or neides.
[41] Metal ions can attract multiple neon atoms to form clusters.
[43] The dipole moment is 3.004 D.[43] Neonium is also formed by excited dihydrogen cation reacting with neon: Ne + H2+* → NeH+ + H[44] The infrared spectrum around 3μm has also been measured.
[45] The Ne*2 molecule exists in an excited state in an excimer lamp using a microhollow cathode.
There is a problem in that there is no window material suitable to transmit these short wavelengths, so it must be used in a vacuum.
Fluorescence was observed by Möller due to bound free transition in a Rydberg molecule of NeH*.
NeH is metastable and its existence was proved by mass spectroscopy in which the NeH+ ion is neutralized and then reionized.
[51] Bokiy's crystallochemical classification of minerals included "compounds of neon" as type 82.
[52] Analogously to the known ArBeO and the predicted HeBeO (beryllium oxide noble gas adducts), NeBeO is expected to exist, albeit with a very weak bond dissociation energy of 9 kJ/mol.