A conceptual approach to hydrogen bonding

Background and Objectives: In spite of the fact that the concept of hydrogen bond has been used for more than a century, not only in chemistry but also in other branches of science, there is still some debit about what this basic term means. Due to the importance of hydrogen bond and lately observed experimental results, in this review an attempt has been made to discuss interesting aspects of the hydrogen bonding concept which are less covered in the text books. Hopefully, his discussion will be beneficial for chemistry teachers and students. Methods: This study was carried out based on literature survey using reliable scientific databases, such as Google Scholar. In this study, an effort was undertaken to examine the gathered information and present a consistent perspective on the definition of hydrogen bond, its categories and related aspects. Findings: By careful study, a practical definition of hydrogen bonding has been obtained. In addition, the various reports about hydrogen bond indicate that it can form not only with nitrogen, oxygen, and fluorine atoms but also, under specific conditions, between other atoms such as boron, carbon and even hydrogen itself. Subsequent sections are devoted to the discussion of symmetric hydrogen bonds and the results of quantum chemical calculations related to this topic. Conclusion: This research, focusing on redefinition of the hydrogen bond, offers a comprehensive review about this subject with particular attention to the symmetric hydrogen bond. Regarding the vast information available on hydrogen bond, this article aims to shed light on certain aspects of this peculiar bond. It is recommended that quantum chemical calculations should be used to further investigate hydrogen bond in order to get a deeper and thorough understanding of this intricate chemical bond.