primary structure

https://doi.org/10.1351/goldbook.P04843
In the context of @M03667@ such as @P04898@, constitutional formula, usually abbreviated to a statement of the @ST06775@ and if appropriate cross-linking of chains.
See also:
secondary structure
,
tertiary structure
,
quaternary structure
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2213 [Terms] [Paper]