Definition of anion in English:



  • A negatively charged ion, i.e., one that would be attracted to the anode in electrolysis.

    The opposite of cation
    • ‘The molecules or anions attached to the central atom are called coordinating groups or ligands.’
    • ‘Non-metals accept electrons in forming anions while metals donate electrons to form cations.’
    • ‘Nitric oxide can react with superoxide anions to produce peroxynitrite anions, thus quenching the biological effects of NO.’
    • ‘An ionic compound is composed of a network of ions that results in a three-dimensional matrix of cations and anions.’
    • ‘When two atoms swap electrons to produce a cation and an anion, the two ions are attracted to each other.’
    • ‘It's easy to make a high oxidation state in an anion because an anion is electron-rich.’
    • ‘These water molecules are ripped apart and change into hydroxyl anions, each of which is negatively charged and has one oxygen ion with a proton attached.’
    • ‘During electrolysis an anion is attracted to the anode (positive electrode).’
    • ‘All the positively charged ions, or cations, are together on the right side of the collage, and all the negatively charged ions, or anions, are on the left.’
    • ‘The cation is positively charged, and the anion is negatively charged.’
    • ‘Cations within the middle solution are attracted to one electrode and anions to the other.’
    • ‘It is called a cation if a positive charge exists and an anion if a negative charge exists.’
    • ‘In an ionic compound there are two different types of ions present, the positively charged cations and the negatively charged anions.’
    • ‘Protons diffuse across a membrane from the anode chamber to the cathode chamber, where they react with the anions to form water or ferrocyanide ions.’
    • ‘A typical reaction of such compounds is to accept an additional electron from an anion or to share electrons with an anion to gain a stable octet.’
    • ‘Crystals of table salt consist of equal numbers of sodium cations and chlorine anions, cation-anion pairs being held together by a force of attraction.’
    • ‘The functional groups of iron hydroxides may sequestrate some cations and anions.’
    • ‘Cations and anions can only exist in ionic compounds, nearly all of which are solids at room temperature, or in solution.’
    • ‘For ions dissolved in water, the rapid exchange of water molecules around the cation usually provides the space for an anion to approach the cation.’
    • ‘To balance the influx of positive charge, organic anions, principally malate, and chloride are also accumulated.’


Mid 19th century: from anode or ana- + ion.