divalente

Divalente is an adjective used in chemistry and related fields to describe something with valence two. In practice, a divalent species has two available bonding sites or a +2 oxidation state. The term can apply to cations, anions, or to ligands with two binding sites. It is contrasted with monovalent species (valence one) and trivalent species (valence three).

Common divalent cations include calcium (Ca2+), magnesium (Mg2+), iron(II) (Fe2+), zinc (Zn2+), strontium (Sr2+), and barium (Ba2+). Some elements can exhibit more than one oxidation state and are not strictly divalent in all contexts; for example, iron exists as Fe2+ and Fe3+. In coordination chemistry, divalent ions readily form complexes and can bridge ligands or participate in chelation.

In biology and medicine, divalent cations play essential roles. Calcium ions (Ca2+) act as key signaling molecules that regulate muscle contraction, neurotransmitter release, and various cellular processes. Magnesium ions (Mg2+) serve as cofactors for numerous enzymes and help stabilize ATP and nucleic acids. Both Ca2+ and Mg2+ are critical for the structure and function of biological macromolecules.

In soils and materials science, divalent cations influence cation exchange on clay minerals and affect the chemical properties of waters and minerals. Their presence alters hardness, precipitation patterns, and the stability of various compounds.