The basic oxides, also known as metallic oxides, are those that combine oxygen with a metal element. Since oxygen is very electronegative and metals are electropositive, the bond that is established is ionic. For instance: dialuminium trioxide (Al2OR3), permanganic oxide (Mn2OR7), zinc oxide (ZnO).
The General Formula representing all basic oxides is XO, where X is the metallic element and O the oxygen. Each of these atoms can be followed by subscripts (generally 2 or 3), which appear by exchanging the valences (that is, that of metal with that of oxygen). The valence of oxygen when it is part of oxides is almost always -2.
Nomenclature of basic oxides
Traditional nomenclature
Basic oxides are named by first mentioning the term “oxide of” and then the name of the metallic element, or “oxide” followed by an adjective (which is the name of the metallic element with different terminations), as detailed below:
- In metals that have only one type of valence, such as sodium (1+) or calcium (2+), the part of the metal is constructed as a spruce word with the ending “ico”. For example: sodium oxide: Na2O / calcium oxide: CaO.
- In metals that have two valences, such as copper (1+ and 2+) or mercury (1+ and 2+), if the oxide involves the lowest valence of the metal, the suffix “bear” is added to the name of the metal and it is a serious word. If it involves the highest valence, the suffix “ico” is added to the name of the metal and it is a sdrújula word. For example: cuprous oxide: Cu2O / cupric oxide: CuO / mercuric oxide: Hg2O / mercuric oxide: HgO
- When there are three possible valences, such as chromium (2+, 3+, 6+), if the oxide involves the lowest valence, the name of the metal is added with the prefix “hypo” and the suffix “bear”, and it is a grave word. When it involves the intermediate valence, the metal is named with the ending “bear” and it is still a grave word, but if it involves the highest valence, the ending is “ico” and it is a sdrújula word. For example: hypochromic oxide: CrO / chromate oxide: Cr2OR3 / chromic oxide: CrO3
- In the metal that has four possible valences, such as manganese (2+, 3+, 4+, 7+), the scheme is the same as the previous one for the first three, but when the metal is integrated into the oxide with the fourth and greater valence, to the name of the metal is added the prefix “per” and the suffix “ico”, and it is a sdrújula word. For example: hypomanganous oxide: MnO / manganous oxide: Mn2OR3 / manganic oxide: MnO2 / permanganic oxide: Mn2OR7.
Nomenclature of Stock
Under this nomenclature, oxides are written and named as “oxide of”+ Metallic element + Roman numeral in parentheses, which indicates the valence with which the metallic element is interacting with oxygen. But if the metallic element has only one valence, this is not indicated in the name of the oxide. For example: Nickel (II) oxide: NiO / Nickel (III) oxide: Ni2OR3 / magnesium oxide: MgO
Systematic nomenclature
This nomenclature is currently the recommended by IUPAC (International Union of Pure and Applied Chemistry). The concept of naming basic oxides as “oxides of” is maintained, but it is done precisely by adding the standard Greek prefix that corresponds to the number of oxygen atoms (to the word “oxide”) and the number of atoms of the metal (to the name of the metal) that each molecule contains, using the preposition “of” as a bridge. The prefixes are: mono (1 atom), di (2 atoms), tri (3 atoms), tetra (4 atoms), penta (5 atoms), and so on. For example: disodium monoxide: Na2O / Nickel Monoxide: NiO / Diiron Trioxide: Fe2OR3
Basic oxides have countless uses in the pharmaceutical, paint, construction materials, plastic and other industries.
Examples of basic oxides
| dialuminium trioxide (Al2OR3) | manganous oxide (Mn2OR3) |
| cobaltous oxide (CoO) | permanganic oxide (Mn2OR7) |
| cupric oxide (CuO) | calcium oxide (CaO) |
| hypochromic oxide (CrO) | zinc oxide (ZnO) |
| ferrous oxide (FeO) | chrome oxide (Cr2OR3) |
| ferric oxide (Fe2OR3) | chromic oxide (CrO3) |
| magnesium oxide (MgO) | mercuric oxide (HgO) |
| plumbous oxide (PbO) | dimanganese trioxide (Mn2OR3) |
| stannous oxide (SnO) | dicobalt trioxide (Co2OR3) |
| stannic oxide (SnO2) | titanium dioxide (TiO2) |
Other types of oxides:
- Metal oxides
- Non-metallic oxides
- Acid oxides