oxide(redirected from Oxides)
Also found in: Dictionary, Thesaurus, Medical.
oxide,chemical compound containing oxygenoxygen,
gaseous chemical element; symbol O; at. no. 8; interval in which at. wt. ranges 15.99903–15.99977; m.p. −218.4°C;; b.p. −182.962°C;; density 1.429 grams per liter at STP; valence −2.
..... Click the link for more information. and one other chemical elementelement,
in chemistry, a substance that cannot be decomposed into simpler substances by chemical means. A substance such as a compound can be decomposed into its constituent elements by means of a chemical reaction, but no further simplification can be achieved.
..... Click the link for more information. . 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 amphoterismamphoterism
, in chemistry, the property of certain substances of acting either as acids or as bases depending on the reaction in which they are involved. Many hydroxide compounds are amphoteric.
..... Click the link for more information. ; i.e., they react with both acids and bases. Still others are neutral and nonreactive.
a chemical compound in which an element is combined with oxygen. Some oxides form salts, for example, Na2O, MgO, Al2O3, SiO2, P2O5, SO3 and C12O7; others, including CO, N2O, NO, and H2O, do not. Oxides that form salts are basic, acid, or amphoteric; accordingly, their hydroxides are bases, acids, or amphoteric compounds. The chemical activity of oxides is determined by the location of the oxidized elements in D. I. Mendeleev’s periodic table of the elements.
Many oxides occur naturally, such as water (H2O), carbon dioxide (CO2), and silica (SiO2, a primary constituent of rocks). The natural oxides of certain elements, including iron and tin, are the starting material for the preparation of the corresponding pure metal. Oxides are widely used in engineering, for example, lime (CaO) is used in construction. Nitric and sulfuric acids are prepared from NO2 and SO2.
a chemical compound in which oxygen is combined only with more electropositive elements. Examples of oxides are chromous oxide (CrO) and chromic oxide:
The term “oxide” has been incorporated into the international nomenclature for inorganic compounds; the equivalent for this term in the Russian nomenclature is okisel.