Chalcogencentered

Chalcogen-centered is a term used in chemistry to describe molecules, ions, or reactive intermediates in which a chalcogen atom—oxygen, sulfur, selenium, tellurium, or polonium—occupies the central position in the molecular framework or bears the primary site of reactivity. The descriptor is applied across inorganic, organometallic, and physical chemistry to highlight the central role of the chalcogen element in bonding, structure, or chemical behavior.

In practice, chalcogen-centered species may arise in several contexts. They can be central cores in structural motifs where the chalcogen atom links two substituents or ligands, or they can be radicals with the unpaired electron localized on the chalcogen atom (chalcogen-centered radicals). They also include chalcogen-centered cations and anions, where the chalcogen plays the defining charge provider or reactive site. In organochalcogen chemistry, chalcogens serve as central atoms in compounds with short, often polarizable bonds to carbon or metal centers, affecting reactivity and catalysis. Chalcogens also participate in coordination chemistry and noncovalent chalcogen bonding, a type of interaction where the chalcogen serves as an electrophilic site for attractive interactions.

The concept is relevant in several fields, including materials science (chalcogenide materials and their electronic properties), catalysis (where the chalcogen center influences redox behavior and Lewis acidity), and medicinal chemistry (organochalcogens as pharmacophores). Safety considerations are noted for heavier chalcogens, such as tellurium and polonium, due to toxicity and radioactivity.

See also: chalcogen, chalcogenide, chalcogen bonding, organochalcogen chemistry.