Molekulidelike

Molekulidelike is a term used in Norwegian-language scientific writing to describe systems, properties, or behaviors that resemble those of discrete molecules rather than extended solid networks. It characterizes substances or phases in which the primary structural units are intact molecular entities, bound to each other mainly by van der Waals forces, hydrogen bonds, or other relatively weak interactions.

The concept appears across chemistry, materials science, and physics. In chemistry, molekulidelike descriptions are applied to molecular liquids and molecular crystals, where individual molecules retain their identity within the condensed phase. In materials science, it can refer to organic–inorganic hybrids or nanoparticle assemblies that behave as if they were single molecules in terms of electronic structure or transport. In physics, certain clusters or quantum-confined systems are described as molekulidelike when their properties are governed by discrete molecular-like energy levels rather than extended band structures.

Key characteristics include: the presence of discrete molecular units with relatively strong intramolecular bonds; interunit interactions that are comparatively weaker; spectroscopic features reflecting individual molecular vibrations; and phase behavior or transport properties that align with molecular rather than lattice-driven models. This contrasts with ionic, covalent-network, or metallic solids, where a continuous lattice and extended bonding dominate.

Examples include molecular liquids such as water or ammonia, molecular crystals like solid CO2 or ice, and nanoscale assemblies where each unit behaves like a separate molecule. The term emphasizes a molecular rather than an extended-solid perspective in describing structure and properties.