Even though hydrogen is the ‘simplest’ atom in the Periodic Table, it has a very rich structural chemistry with eight bonding types. This chapter discusses the nature of the hydrogen bond, non-conventional hydrogen bonds (X-H···, X-H···M, X-H···H-E, etc.), hydride complexes, molecular hydrogen coordination compounds, and -bond complexes.
Keywords: agnostic bond, dihydrogen bond, hydride complex, hydrogen bonding, hydrogen bridging bond, isotopes of hydrogen, molecular hydrogen coordination compounds, polymeric hydrogen, -bond complexes