A set of N atoms moving in 3-dimensional space has 3N degrees of freedom.

The extra energy of a configuration with N atoms is changed by μ"N".

Scopoletin has no N atoms and is not an alkaloid.

The free H and N atoms escape into space leaving O in the atmosphere:

A one-dimensional quantum mechanical harmonic chain consists of N identical atoms.

NOTE: the structure of sparteine shown below is missing a N atom.

The pyridine base in the axial position can also be replaced by other organic bases containing a sp hybridized N atom as well.

Consider a one-dimensional quantum mechanical harmonic chain of N identical atoms.

Succinylcholine has a 10-atom distance between its N atoms, like decamethonium.

The four methyl-groups on the quaternary N atoms make it less lipophilic than most aminosteroids.