##  [Molecule](/molecule-0) 

 Definition

A discrete assembly of two or more atoms held together by chemical bonds that behaves as an independent chemical species.

 

 

 

 

 

 





## Principle

Principle

Chemical bonds—covalent, ionic, coordinate, metallic, and weaker intermolecular forces—determine the stability, geometry, and emergent properties of a molecule; electronic structure and molecular orbitals explain reactivity and spectra.

 

 

 

 

 





## Demonstration

Demonstration

A water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom in a bent geometry; its polar bonds and overall dipole explain solvent behavior and hydrogen bonding.

 

 

 

 

## Misapplication

Misapplication

Calling an extended ionic lattice or network solid a 'molecule' (for example treating crystalline sodium chloride as discrete NaCl molecules) or ignoring that some assemblies are supramolecular complexes rather than single covalently bound molecules.

 

 

 

 

 





## Consequence

Consequence

Identifying molecular composition and structure enables prediction of reactivity, physical properties, and spectroscopic signatures, and guides synthesis and functional design in chemistry and biology.

 

 

 

 

## Reversal

Reversal

A single atom or an infinite periodic solid (network covalent or ionic lattice) that lacks a well-defined discrete molecular unit.

 

 

 

 

 





## Boundary

Boundary

Applies to discrete bonded assemblies of atoms (neutral or charged) considered as single chemical entities; excludes truly extended solids without discrete molecular units and purely physical aggregates lacking defined bonding topology.

 

 

 

 

 





## Semantic Tension

Semantic Tension

Tension between molecule and supramolecular assembly, and between molecular description and band/solid-state descriptions where electronic delocalization makes single-molecule concept less useful.

 

 

 

 

 





## Synthesis

Synthesis

A molecule is a stable assembly of atoms connected by defined bonding interactions whose electronic structure and geometry determine its distinct chemical identity, properties, and reactivity, distinct from single atoms and extended solids.