Co1Co4

Co1Co4 is a notation used in crystallography and materials science to describe cobalt-containing structures in which cobalt atoms occupy two distinct crystallographic sites labeled Co1 and Co4. It does not denote a simple molecular formula; rather, it indicates a site-occupancy pattern: the Co1 site refers to a unique, often lower-symmetry position, while the Co4 sites denote a set of symmetry-related positions that host cobalt atoms. The overall chemical formula derived from the full structure depends on all sites and their occupancies.

In typical interpretations, the Co1 site may have a different coordination environment or bond lengths than the Co4 sites. In ordered intermetallics or compounds, Co1 and Co4 may be fully cobalt-occupied, while in alloys or disordered variants, one of the sites may be substituted by another element or partially occupied.

Synthesis and discovery: The designation arises from diffraction studies (X-ray, neutron) of cobalt-containing alloys, intermetallics, or clusters, where distinguishing inequivalent cobalt environments is necessary to refine the structural model. The information helps correlate local structure with properties such as magnetism and catalytic activity.

See also: Wyckoff position, site occupancy disorder, intermetallic compound, cobalt alloy.