The United States of America National Committee for Crystallography (USNC/Cr) represents U.S. crystallographers in the International Union of Crystallography (IUCr) through the National Academy of Sciences. The IUCr strives to promote international cooperation and publication in crystallography; to facilitate standardization of methods, units, nomenclatures and symbols; and to form a focus for the relations of crystallography to other sciences.

The photo above depicts a fragment of the world largest molecular structure model (NaCl).