An oxide is a chemical compound that contains at least one oxygen atom and another element. Almost every element can form an oxide, with the exception of lighter inert gasses like helium and neon. Oxides can be ionic or covalent. Metals with low oxidation states form ionic oxides, while those with high oxidation states form covalent oxides. Nonmetals also form covalent oxides, which usually have a molecular structure. Oxide minerals have structures based on close-packed oxygen atoms with positively charged metal ions in the gaps. They are different from silicates, borates, and carbonates, which have definable groups containing oxygen atoms covalently bonded to another element. Rare-earth elements form many oxides, with the most common form having the formula R2O3.

How are oxides formed?

Oxides form when oxygen combines with another element; with the exception of lighter inert gasses, oxygen can form at least one binary oxide with each of the elements. Both metals and nonmetals can reach their highest oxidation states in oxygen compounds. Alkali, alkaline earth, transition, and post-transition metals form ionic oxides. Metals with high oxidation states form oxides with more covalent bonds. Nonmetals also form covalent oxides, typically molecular. As the periodic table moves from left to right, a smooth transition from ionic to covalent bonding occurs. Some organic compounds react with oxygen or oxidizing agents to form oxides. Amines, phosphines, and sulfides, for example, produce amine oxides, phosphine oxides, and sulfoxides, respectively, where the oxygen atom is covalently bonded to the nitrogen, phosphorus, or sulfur atom. Olefin oxides are cyclic ethers. Oxygen can be produced in the laboratory through thermal decomposition of salts, oxides of heavy metals, metal peroxides, or hydrogen peroxide, or by electrolysis of water.

What are some common examples of oxides?

Oxides are chemical compounds where oxygen combines with another element. Common examples include: * Metal oxides such as magnesium oxide (MgO) used in thermal insulation, and calcium oxide (CaO), or quicklime, used in steel production and water purification. * Nonmetal oxides like carbon monoxide (CO) and carbon dioxide ((CO_2)), both oxides of carbon. * Organic oxides such as amine oxides, phosphine oxides, and sulfoxides. Metal oxides typically react with water to form bases or with acids to form salts, while nonmetal oxides react with water to form acids or with bases to form salts.

How do metal oxides and nonmetal oxides differ?

Oxides are chemical compounds that contain oxygen combined with another element. Metal oxides and nonmetal oxides differ in their structure, bonding, and behavior. Metal oxides typically consist of a metal cation and an oxide anion and often react with water to form bases or with acids to form salts. Metal oxides are generally ionic, and their basicity increases down a group. Nonmetal oxides are covalent compounds. They react with water to form acids or with bases to form salts. Most nonmetal oxides are acidic and yield hydronium ions in aqueous solution.

What role do oxides play in our daily lives?

Oxides play a significant role in daily life. An oxide is a compound where oxygen combines with another element. Examples and uses of oxides: * Rust , or iron oxide, forms when iron reacts with oxygen and moisture. Rust can be prevented through treatments like coating, painting, or galvanizing. * Silicon dioxide (silica) is used in concrete and bricks, and can be heated and shaped into glassware. It is also used as an abrasive, in the production of glass and ceramics, and as an adsorbent. * Zinc oxide is used for mildew control in paints. * Titanium dioxide is a white pigment used in paint. * Magnesium oxide is a thermal conductor and electrical insulator used in firebrick and thermal insulation. * Calcium oxide (lime) is used in the steel industry and in water purification.

How can oxides impact the environment?

Oxides significantly impact the environment through air pollution, contributing to acid rain and harming plant and animal life. Sulfur oxides, such as sulfur dioxide ((SO_2)), released from burning coal and oil, dissolve in atmospheric water droplets, forming damaging acidic solutions. Nitrogen oxides, including nitrogen dioxide, from power plants and vehicles, also contribute to acid rain and cause respiratory issues. Furthermore, nitrogen dioxide plays a role in forming photochemical smog in urban areas, leading to eye and chest irritation. Carbon dioxide ((CO_2)), a key greenhouse gas, has increased dramatically due to combustion, leading to concerns about rising air temperatures and climate change. Additionally, oxides in the soil, such as metal oxides and excess salinity, can result in toxicity hazards, impacting ecosystems and potentially affecting human health.

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The structures of phosphorus(III) oxide, P4O6, and phosphorus(V) oxide, P4O10, both based on the tetrahedral structure of elemental white phosphorus, P4. Bond lengths are given in picometres (pm; 1 picometre = 10-12 metre).

Figure 19: Summary of shock-wave data on the densities of oxides and iron compounds at high pressures and high temperatures. The seismologically derived pressure-density curves for the lower mantle and outer core are included for comparison.

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Top Questions

What is an oxide?
An oxide is a chemical compound that contains at least one oxygen atom and another element. Almost every element can form an oxide, with the exception of lighter inert gasses like helium and neon.

Oxides can be ionic or covalent. Metals with low oxidation states form ionic oxides, while those with high oxidation states form covalent oxides. Nonmetals also form covalent oxides, which usually have a molecular structure.

Oxide minerals have structures based on close-packed oxygen atoms with positively charged metal ions in the gaps. They are different from silicates, borates, and carbonates, which have definable groups containing oxygen atoms covalently bonded to another element.

Rare-earth elements form many oxides, with the most common form having the formula R2O3.
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How are oxides formed?
Oxides form when oxygen combines with another element; with the exception of lighter inert gasses, oxygen can form at least one binary oxide with each of the elements.

Both metals and nonmetals can reach their highest oxidation states in oxygen compounds. Alkali, alkaline earth, transition, and post-transition metals form ionic oxides. Metals with high oxidation states form oxides with more covalent bonds. Nonmetals also form covalent oxides, typically molecular. As the periodic table moves from left to right, a smooth transition from ionic to covalent bonding occurs.

Some organic compounds react with oxygen or oxidizing agents to form oxides. Amines, phosphines, and sulfides, for example, produce amine oxides, phosphine oxides, and sulfoxides, respectively, where the oxygen atom is covalently bonded to the nitrogen, phosphorus, or sulfur atom. Olefin oxides are cyclic ethers.

Oxygen can be produced in the laboratory through thermal decomposition of salts, oxides of heavy metals, metal peroxides, or hydrogen peroxide, or by electrolysis of water.
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What are some common examples of oxides?
Oxides are chemical compounds where oxygen combines with another element.

Common examples include:
* Metal oxides such as magnesium oxide (MgO) used in thermal insulation, and calcium oxide (CaO), or quicklime, used in steel production and water purification.
* Nonmetal oxides like carbon monoxide (CO) and carbon dioxide ((CO_2)), both oxides of carbon.
* Organic oxides such as amine oxides, phosphine oxides, and sulfoxides.

Metal oxides typically react with water to form bases or with acids to form salts, while nonmetal oxides react with water to form acids or with bases to form salts.
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How do metal oxides and nonmetal oxides differ?
Oxides are chemical compounds that contain oxygen combined with another element. Metal oxides and nonmetal oxides differ in their structure, bonding, and behavior.

Metal oxides typically consist of a metal cation and an oxide anion and often react with water to form bases or with acids to form salts. Metal oxides are generally ionic, and their basicity increases down a group.

Nonmetal oxides are covalent compounds. They react with water to form acids or with bases to form salts. Most nonmetal oxides are acidic and yield hydronium ions in aqueous solution.
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1. oxide: Metal oxides
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What role do oxides play in our daily lives?
Oxides play a significant role in daily life. An oxide is a compound where oxygen combines with another element.

Examples and uses of oxides:
* Rust, or iron oxide, forms when iron reacts with oxygen and moisture. Rust can be prevented through treatments like coating, painting, or galvanizing.
* Silicon dioxide (silica) is used in concrete and bricks, and can be heated and shaped into glassware. It is also used as an abrasive, in the production of glass and ceramics, and as an adsorbent.
* Zinc oxide is used for mildew control in paints.
* Titanium dioxide is a white pigment used in paint.
* Magnesium oxide is a thermal conductor and electrical insulator used in firebrick and thermal insulation.
* Calcium oxide (lime) is used in the steel industry and in water purification.
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How can oxides impact the environment?
Oxides significantly impact the environment through air pollution, contributing to acid rain and harming plant and animal life. Sulfur oxides, such as sulfur dioxide ((SO_2)), released from burning coal and oil, dissolve in atmospheric water droplets, forming damaging acidic solutions. Nitrogen oxides, including nitrogen dioxide, from power plants and vehicles, also contribute to acid rain and cause respiratory issues. Furthermore, nitrogen dioxide plays a role in forming photochemical smog in urban areas, leading to eye and chest irritation.

Carbon dioxide ((CO_2)), a key greenhouse gas, has increased dramatically due to combustion, leading to concerns about rising air temperatures and climate change. Additionally, oxides in the soil, such as metal oxides and excess salinity, can result in toxicity hazards, impacting ecosystems and potentially affecting human health.
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oxide, any of a large and important class of chemical compounds in which oxygen is combined with another element. With the exception of the lighter inert gases (helium [He], neon [Ne], argon [Ar], and krypton [Kr]), oxygen (O) forms at least one binary oxide with each of the elements.

Both metals and nonmetals can attain their highest oxidation states (i.e., donate their maximum number of available valence electrons) in compounds with oxygen. The alkali metals and the alkaline earth metals, as well as the transition metals and the posttransition metals (in their lower oxidation states), form ionic oxides—i.e., compounds that contain the O²⁻ anion. Metals with high oxidation states form oxides whose bonds have a more covalent nature. Nonmetals also form covalent oxides, which are usually molecular in character. A smooth variation from ionic to covalent in the type of bonding in oxides is observed as the periodic table is traversed from the metals on the left to the nonmetals on the right. This same variation is observed in the reaction of oxides with water and the resulting acid-base character of the products. Ionic metal oxides react with water to give hydroxides (compounds containing the OH⁻ ion) and resultant basic solutions, whereas most nonmetal oxides react with water to form acids and resultant acidic solutions (see the table).

Periodic variation of the properties of oxides of the elements of the third period
	group 1	group 2	group 13	group 14	group 15	group 16	group 17
Source: From W. Robinson, J. Odom, and H. Holtzclaw, Jr., Chemistry: Concepts and Models, D.C. Heath and Co., 1992.
reaction of oxides with water and the acid-base character of hydroxides	Na₂O gives NaOH (strong base)	MgO gives Mg(OH)₂ (weak base)	Al₂O₃ nonreacting	SiO₂ nonreacting	P₄O₁₀ gives H₃PO₄ (weak acid)	SO₃ gives H₂SO₄ (strong acid)	Cl₂O₇ gives HClO₄ (strong acid)
bonding in oxides	Na₂O ionic	MgO ionic	Al₂O₃ ionic	SiO₂ covalent	P₄O₁₀ covalent	SO₃ covalent	Cl₂O₇ covalent

Certain organic compounds react with oxygen or other oxidizing agents to produce substances called oxides. Thus, amines, phosphines, and sulfides form amine oxides, phosphine oxides, and sulfoxides, respectively, in which the oxygen atom is covalently bonded to the nitrogen, phosphorus, or sulfur atom. The so-called olefin oxides are cyclic ethers.

Metal oxides

Metal oxides are crystalline solids that contain a metal cation and an oxide anion. They typically react with water to form bases or with acids to form salts.

The alkali metals and alkaline earth metals form three different types of binary oxygen compounds: (1) oxides, containing oxide ions, O²⁻, (2) peroxides, containing peroxide ions, O₂²⁻, which contain oxygen-oxygen covalent single bonds, and (3) superoxides, containing superoxide ions, O₂⁻, which also have oxygen-oxygen covalent bonds but with one fewer negative charge than peroxide ions. Alkali metals (which have a +1 oxidation state) form oxides, M₂O, peroxides, M₂O₂, and superoxides, MO₂. (M represents a metal atom.) The alkaline earth metals (with a +2 oxidation state) form only oxides, MO, and peroxides, MO₂. All the alkali metal oxides can be prepared by heating the corresponding metal nitrate with the elemental metal. 2MNO₃ + 10M + heat → 6M₂O + N₂ A general preparation of the alkaline earth oxides involves heating the metal carbonates. MCO₃ + heat → MO + CO₂ Both alkali metal oxides and alkaline earth metal oxides are ionic and react with water to form basic solutions of the metal hydroxide. M₂O + H₂O → 2MOH (where M = group 1 metal)
MO + H₂O → M(OH)₂ (where M = group 2 metal) Thus, these compounds are often called basic oxides. In accord with their basic behaviour, they react with acids in typical acid-base reactions to produce salts and water; for example, M₂O + 2HCl → 2MCl + H₂O (where M = group 1 metal). These reactions are also often called neutralization reactions. The most important basic oxides are magnesium oxide (MgO), a good thermal conductor and electrical insulator that is used in firebrick and thermal insulation, and calcium oxide (CaO), also called quicklime or lime, used extensively in the steel industry and in water purification.

Periodic trends of the oxides have been thoroughly studied. In any given period, the bonding in oxides progresses from ionic to covalent, and their acid-base character goes from strongly basic through weakly basic, amphoteric, weakly acidic, and finally strongly acidic. In general, basicity increases down a group (e.g., in the alkaline earth oxides, BeO < MgO < CaO < SrO < BaO). Acidity increases with increasing oxidation number of the element. For example, of the five oxides of manganese, MnO (in which manganese has an oxidation state of +2) is the least acidic and Mn₂O₇ (which contains Mn⁷⁺) the most acidic. Oxides of the transition metals with oxidation numbers of +1, +2, and +3 are ionic compounds consisting of metal ions and oxide ions. Those transition metal oxides with oxidation numbers +4, +5, +6, and +7 behave as covalent compounds containing covalent metal-oxygen bonds. As a general rule, the ionic transition metal oxides are basic. That is, they will react with aqueous acids to form solutions of salts and water; for example, CoO + 2H₃O⁺ → Co²⁺ + 3H₂O. The oxides with oxidation numbers of +5, +6, and +7 are acidic and react with solutions of hydroxide to form salts and water; for example, CrO₃ + 2OH^- → CrO₄²⁻ + H₂O. Those oxides with +4 oxidation numbers are generally amphoteric (from Greek amphoteros, “in both ways”), meaning that these compounds can behave either as acids or as bases. Amphoteric oxides dissolve not only in acidic solutions but also in basic solutions. For example, vanadium oxide (VO₂) is an amphoteric oxide, dissolving in acid to give the blue vanadyl ion, [VO]²⁺, and in base to yield the yellow-brown hypovanadate ion, [V₄O₉]²⁻. Amphoterism among the main group oxides is primarily found with the metalloidal elements or their close neighbours.

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Metal oxides