Ion

We explain what an ion is and how it is constituted and some examples. Also, what is an anion and a cation.

What is an ion?

In chemistry, it is known as the a ion. an electrically charged particle and that it is made up of an atom or molecule that is not electrically neutral, that is, that in its constitution it has gained or lost electrons. The process by which ions are produced is called “ionization.”

The ions can be made up of two or more atoms (polyatomic) of diverse nature, or of a single atom (monatomic). In any case, we will talk about a cation (or cations) when it is a positively charged ion (that is, the initial neutral atom or molecule gave up electrons), and we will talk about a anion (or anions) when it is a negatively charged ion (that is, the initial neutral atom or molecule accepted electrons).

Other types of ions are also known, based on their electrical charge, known as dianions (when they have two negative charges), zwitterions (when they have a positive and a negative charge that are isolated, but in the same compound, because it is neutral), or ionic radicals (ions of enormous reactivity and instability because they have free electrons). In general terms, the ions are very reactive and they tend to combine with other ions, atoms or molecules through electrostatic interactions.

The ions play an indispensable role in life, especially those of calcium, potassium and sodium whose importance in the transit of cell membranes and neurotransmitters has been widely studied. Furthermore, the understanding of ions has allowed us to develop plasma technology and even measure the quality of water based on the ionic salts dissolved in it.

See also: Chemical bond

Anion

It is known as anion (or anions) ions that have a negative electrical charge that is, they have gained electrons in a chemical reaction that gave rise to them. They can be made up of one or several atoms, but even in the latter case the overall charge of the molecule (its oxidation state) is always negative.

There are three types of anions:

• Monatomic. Those made up of a single atom that has gained electrons. For example: Chloride (Cl^–).
• Polyatomic. They come from a molecule that has gained electrons in a chemical reaction, or from an acid that has lost protons. For example: Sulfite (SO₃^2-).
• Acids. They come from a polyprotic acid (which has multiple ionizable hydrogens) from which protons have been extracted. For example: Diahydrogen phosphate (H₂PO₄^–).

Cation

The cations are ions that have a positive electrical charge that is, they have lost one or more electrons. Thus, like anions, cations can also be composed of one or more atoms, as long as the total charge of the compound, in this case, is positive.

One of the most important functions of cations is their participation in biological processes. For example, Na cations⁺ and K.⁺ They play a fundamental role in the transmission of nerve impulses.

Examples of ion

The best known ions are:

• simple cations Composed of a single atom with a positive charge:
  • Aluminum (Al³⁺)
  • Cesium (Cs⁺)
  • Chromium (III) or chromic ion (Cr³⁺)
  • Chromium (VI) or perchromic ion (Cr⁶⁺)
  • Hydrogen or proton (H⁺)
  • Helium or alpha particle (He²⁺)
  • Lithium (Li⁺)
  • Iron (II) or ferrous ion (Fe²⁺)
  • Iron (III) or ferric ion (Fe³⁺)
  • Nickel (III) or nickel ion (Ni³⁺)
  • Tin (II) or stannous ion (Sn²⁺)
  • Tin (IV) or stanic ion (Sn⁴⁺)
• Polyatomic cations. Composed of two or more positively charged atoms:
  • Ammonium (NH₄⁺)
  • Oxonium (H₃EITHER⁺)
  • Nitronium (NO₂⁺)
  • Mercury (I) or mercurous ion (Hg₂²⁺)
• simple anions Composed of a single negatively charged atom:
  • Azide (N₃^–)
  • Bromide (Br^–)
  • Carbide (C^4-)
  • Chloride (Cl^–)
  • Fluoride (F^–)
  • Phosphide (P^3-)
  • Nitride (N^3-)
  • Sulfide (S^2-)
• Oxoanions Composed of oxygen and other elements, they have a negative charge:
  • Arsenate (AsO₄^3-)
  • Borate (BO₃^3-)
  • Hypobromite (BrO^–)
  • Bicarbonate (HCO₃^–)
  • Chlorate (ClO₃^–)
  • Chlorite (ClO₂^–)
  • Hypochlorite (ClO^–)
  • Dichromate (Cr₂EITHER₇^2-)
  • Hydrogen sulfate or bisulfate (HSO₄^–)
  • Hydrogen sulfite or bisulfite (HSO₃^–)
  • Silicate (SiO₄^4-)
• Anions of organic acids. Coming from organic molecules, they have a negative charge:
  • Acetate (C₂h₃EITHER₂^–)
  • Oxalate (C₂EITHER₄^2-)
  • Bioxalate (HC₂EITHER₄^–)
• Other anions. With a negative charge and more than one atom:
  • Disulfide (HS^–)
  • Amidide (NH₂^–)
  • Cyanate (OCN^–)
  • Thiocyanate (SCN^–)
  • Cyanide (CN^–)
  • Hydroxide (OH^–)