What is oxide?

Oxideit's a substance inorganic binary (formed by two different chemical elements) in which one of the elements is oxygen (acronym O), which is the most electronegative element and presents NOX equal to -2.

General formula of an oxide

See too:What is NOX?

1- Types of oxides

• Ionic: are oxides that present metal following the oxygen in the composition;

• Molecular: are oxides that present ametal following the oxygen in the composition.

In general, if the oxide is ionic or molecular, we can use the following official naming rule:

Prefix + oxide + de + prefix + element name

Example: Cl₂O₅ → Dichlorine pentoxide

Note: The prefix is ​​related to the amount of oxygen or the element that accompanies oxygen → 2 (di), 3 (tri), 4 (tetra), 5 (penta) etc.

For ionic oxides, we can use two other rules:

• If the element has fixed NOX (belonging to the IA, IIA, IIIA families or is it zinc or silver):

Oxide + de + element name

Example: CaO → calcium oxide

• If the element does not have fixed NOX:

Oxide + de + element name + roman numeral

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Note: The Roman numeral is the NOX of the element.

Example: Cr₂O₃ → chromium oxide III

• Double, mixed or saline: are ionic oxides that have Y₃O₄ as a general formula. In water, they form two bases and when they react with acids or bases, they form two salts and water;

• Amphoters: When these oxides react with acid or base, form salt and water. Can be:

  → ionic oxides that have in their composition the metals beryllium (acronym Be), aluminum (acronym Al), chromium (acronym Cr; NOX +3), zinc (acronym Zn), tin (acronym Sn), lead (acronym Pb);

  → molecular oxides that have the elements antimony (acronym Sb) or arsenic (acronym As).

• Basics: ionic oxides that have any other metal (except chromium, which only forms a basic oxide if it has NOX +2). In water they form bases and, in the presence of acid, form salt and water;

• Neutrals: are the molecular oxides carbon monoxide (CO), nitrogen monoxide (NO) and dinitrogen monoxide (N₂O). Do not react with water, base or salt;

• Acids: any other molecular oxide and chromium oxide (provided it has NOX +6). In water, they form acids and, in the presence of a base, form salt and water.

By Me. Diogo Lopes Dias

Would you like to reference this text in a school or academic work? Look:

DAYS, Diogo Lopes. "What is oxide?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/quimica/o-que-e-oxido.htm. Accessed on June 27, 2021.