What is the definition of an H bond in chemistry?

The definition of an H bond, or hydrogen bond, refers to a weak attraction between a hydrogen atom and an electronegative atom, such as oxygen or nitrogen. This type of bonding occurs because hydrogen, when covalently bonded to an electronegative atom, takes on a partial positive charge. The partial positive charge of the hydrogen atom then creates an attraction to other electronegative atoms that carry a partial negative charge, which results in the formation of hydrogen bonds. These interactions are critical in biological systems, as they help to stabilize structures like DNA and proteins, contributing to their function and properties.

The other options describe different types of bonding, but they do not accurately capture the specific nature of hydrogen bonds. A bond formed between two metals would pertain to metallic bonding, which is distinct from the weak attractions seen in hydrogen bonding. A strong covalent bond refers to a much stronger connection formed by the sharing of electrons between atoms, which is fundamentally different from the weak, attractive nature of hydrogen bonds. Lastly, a bond formed by electron sharing typically describes covalent bonds rather than the specific interaction characterized by hydrogen bonding.