oxide

oxide, chemical compound containing oxygen and one other chemical element. Oxides are widely and abundantly distributed in nature. Water is the oxide of hydrogen. Silicon dioxide is the major component of sand and quartz. Carbon dioxide is given off during respiration by animals and plants. Carbon monoxide, sulfur dioxide, and oxides of nitrogen are among the waste gases of gasoline-burning internal-combustion engines. Nitrous oxide is an oxide of nitrogen often called laughing gas. Many of the metals form oxides. Some metal oxides, e.g., those of iron, aluminum, tin, and zinc, are important as ores. Litharge and red lead are lead oxides used as pigments in paint. A number of elements, e.g., arsenic, carbon, manganese, nitrogen, phosphorous, and sulfur, combine with oxygen to form more than one oxide. The inert gases do not form oxides. The halogens and inactive metals do not combine directly with oxygen, but their oxides can be formed by indirect methods. Oxides are usually named according to the number of oxygen atoms present in a molecule, e.g., monoxide (or simply oxide), dioxide, trioxide. In a molecule of carbon monoxide, CO, for example, there is one oxygen atom; in carbon dioxide, CO₂, there are two; and in phosphorus pentoxide, P₂O₅, there are five. Oxides are commonly classified as acidic or basic oxides or anhydrides. Sulfur trioxide is an acid anhydride; it reacts with water to form sulfuric acid. Phosphorus pentoxide reacts vigorously with water to form phosphoric acid. Many metal oxides react with water to form alkaline hydroxides, e.g., calcium oxide (lime) reacts with water to form calcium hydroxide (slaked lime). Some metal oxides do not react with water but are basic in that they react with an acid to form a salt and water. Others exhibit amphoterism; i.e., they react with both acids and bases. Still others are neutral and nonreactive.

---

oxide

Any of a large and important class of chemical compounds in which oxygen is combined with another element. Metal oxides contain a metal cation and the oxide anion (O₂⁻); they typically react with water to form bases or with acids to form salts. Oxides of nonmetallic elements are volatile compounds in which a covalent bond joins the oxygen and the nonmetal; they react with water to form acids or with bases to form salts. A few substances (e.g., aluminum, zinc) form amphoteric oxides, which form salts with both acids and bases. Certain organic compounds form oxides in which the oxygen is covalently bonded to an atom of nitrogen (amine oxides), phosphorus (phosphine oxides), or sulfur (sulfoxides) in the organic molecule.

---

oxide

1. any compound of oxygen with another element

2. any organic compound in which an oxygen atom is bound to two alkyl or aryl groups; an ether or epoxide

---

oxide [′äk‚sīd]

(chemistry)

Binary chemical compound in which oxygen is combined with a metal (such as Na₂O; basic) or nonmetal (such as NO₂; acidic).