Neonargon

Neonargon is a term found in some scientific literature to describe a transient van der Waals complex formed between neon and argon atoms. It is not a true chemical compound in the sense of covalent bonding; noble gases typically interact only through weak dispersion forces. The Ne–Ar entity is therefore considered a fragile, nonpolar dimer that exists only under special conditions, such as in cryogenic gas-phase experiments, supersonic jet expansions, or within cryogenic matrix environments.

Structure, properties and detection: As a van der Waals complex, neonargon exhibits extremely weak intermolecular bonding. Its existence is inferred from spectroscopic measurements that reveal bound-state transitions corresponding to intermolecular motions. Because the binding is very shallow, the complex has a short lifetime in the gas phase and is difficult to observe without sensitive, high-resolution techniques. In matrix isolation or cold-jet setups, NeAr can be stabilized long enough to study its spectroscopic signature.

Formation and environments: NeAr can be formed by careful co-generation or co-deposition of neon and argon under cryogenic conditions, or by clustering techniques in cold jet expansions. Its signals are typically detected through infrared or microwave spectroscopy, where small shifts and newly observed lines indicate the presence of a Ne–Ar interaction within a larger system of inert gas atoms.

Applications and significance: Studying neonargon helps researchers understand weak intermolecular forces and quantum effects in noble gas clusters. It serves as a reference system for calibrating spectroscopic methods and testing theoretical models of van der Waals interactions. Related species include other noble gas dimers and larger van der Waals clusters like Ne2 and Ar2.