Exploring tetrel bonding: a special issue of Acta Cryst. C

Halogen bonding and related intermolecular (and sometimes intramolecular) interactions in which p-block elements in groups other than Group 17 serve in a Lewis acidic role have been and continue to be extensively investigated. Their applicability in supramolecular assembly is similarly well studied, with numerous reports of applications in crystal engineering, molecular recognition, catalysis, polymers and soft matter, materials chemistry, structural biology and medicinal chemistry.

This virtual special issue of Acta Crystallographica Section C: Structural Chemistry, titled "Halogen, chalcogen, pnictogen and tetrel bonds: structural chemistry and beyond", brings together 12 articles that cover a variety of aspects associated with halogen, chalcogen, pnictogen and tetrel bonds. The issue is introduced by a review by the Guest Editors, Lee Brammer, Anssi Peuronen and Thomas M. Roseveare. In "Halogen bonds, chalcogen bonds, pnictogen bonds, tetrel bonds and other σ-hole interactions: a snapshot of current progress", they present a compilation of review articles on σ-hole interactions published since 2013 alongside an overview of the 11 articles in the special issue on this topic.

There are articles that focus on structure, bonding and bond strength, articles that investigate co-operation or competition between different classes of interactions and articles that explore the relationship between these interactions and chemical or physical properties of the compounds and materials involved. Although all articles involve characterization by single-crystal X-ray diffraction, a number have a prominent focus on other experimental techniques or are combined with interpretation from theoretical calculations. Halogen bonding and chalcogen bonding dominate these articles, consistent with the wider literature.