Oxide 22305 224304465 2008-07-08T07:01:57Z ClueBot 4928500 Reverting possible vandalism by [[Special:Contributions/84.164.85.212|84.164.85.212]] to version by Kwjbot. False positive? [[User:ClueBot/FalsePositives|Report it]]. Thanks, [[User:ClueBot]]. (434913) (Bot) An '''oxide''' is a [[chemical compound]] containing at least one [[oxygen]] atom as well as at least one other element. Most of the [[Earth's crust]] consists of oxides. Oxides result when elements are oxidized by oxygen in [[air]]. Combustion of [[hydrocarbon]]s affords the two principal oxides of [[carbon]], [[carbon monoxide]] and [[carbon dioxide]]. Even materials that are considered to be pure elements often contain a coating of oxides. For example, [[aluminium foil]] has a thin skin of [[alumina|Al<sub>2</sub>O<sub>3</sub>]] that protects the foil from further [[corrosion]]. Virtually all elements burn in an atmosphere of oxygen. In the presence of water and oxygen (or simply air), some elements - [[lithium]], [[sodium]], [[potassium]], [[rubidium]], [[caesium]], [[strontium]] and [[barium]] - react rapidly, even dangerously to give the hydroxides. In part for this reason, alkali and alkaline earth metals are not found in nature in their metallic, i.e., native, form. Caesium is so reactive with oxygen that it is used as a [[getter]] in [[vacuum tube]]s, and solutions of potassium and sodium, so called [[NaK]] are used to deoxygenate and dehydrate some organic solvents. The surface of most metals consist of oxides and hydroxides in the presence of air. A well known example is [[aluminium foil]], which is coated with a thin film of [[aluminium oxide]] that [[passivation|passivates]] the metal, slowing further [[corrosion]]. The aluminium oxide layer can be built to greater thickness by the process of [[electrolysis|electrolytic]] [[anodising]]. Although solid magnesium and aluminium react slowly with oxygen at [[Standard conditions for temperature and pressure|STP]], they, like most metals, will burn in air, generating very high temperatures. As a consequence, finely divided powders of most metals can be dangerously explosive in air. [[Image:Rust screw.jpg|thumb|left|Oxides, such as [[iron oxide]] or [[rust]], Fe<sub>2</sub>O<sub>3</sub>, form when oxygen combines with other elements]] In dry oxygen, [[iron]] readily forms [[iron(II) oxide]], but the formation of the hydrated ferric oxides, Fe<sub>2</sub>O<sub>3−2x</sub>(OH)<sub>x</sub>, that mainly comprise rust, typically requires oxygen ''and'' water. The production of free oxygen by [[photosynthesis|photosynthetic]] [[bacteria]] some 3.5 billion years ago [[precipitate]]d iron out of solution in the oceans as Fe<sub>2</sub>O<sub>3</sub> in the economically-important [[banded iron formations|iron ore]] [[hematite]]. Due to its [[electronegativity]], oxygen forms [[chemical bond]]s with almost all elements to give the corresponding oxides. So-called noble metals (common examples: [[gold]], [[platinum]]) resist direct chemical combination with oxygen, and substances like [[gold(III) oxide]] must be generated by indirect routes. ==Insolubility in water== The oxide [[ion]], O<sup>2−</sup>, is the [[conjugate acid|conjugate base]] of the [[hydroxide]] ion, OH<sup>−</sup>, and is encountered in [[ionic compound|ionic]] solid such as [[calcium oxide]]. O<sup>2−</sup> is unstable in [[water|aqueous]] [[solution]] − its affinity for H<sup>+</sup> is so great (p''K''<sub>b</sub> ~ −22) that it abstracts a [[proton]] from a solvent H<sub>2</sub>O molecule: :O<sup>2−</sup> + H<sub>2</sub>O → 2 OH<sup>−</sup> Although many [[anion]]s are stable in aqueous solution, ionic oxides are not.<!--period: they "dissolve by reacting--> For example, [[sodium chloride]] dissolves readily in water to give a solution containing the constituent ions, Na<sup>+</sup> and Cl<sup>−</sup>. Oxides do not behave like this. If an ionic oxide dissolves, the O<sup>2−</sup> ions become protonated. Although [[calcium oxide]], CaO, is said to "dissolve" in water, the products include [[hydroxide]]: :CaO + H<sub>2</sub>O → Ca<sup>2+</sup> + 2 OH<sup>−</sup> In fact, no monoatomic dianion is known to dissolve in water - all are so basic that they undergo [[hydrolysis]]. Concentrations of oxide ion in water are too low to be detectable with current technology. Authentic soluble oxides do exist, but they release [[oxyanion]]s, not O<sup>2−</sup>. Well known soluble salts of oxyanions include [[sodium sulfate]] (Na<sub>2</sub>SO<sub>4</sub>), [[potassium permanganate]] (KMnO<sub>4</sub>), and sodium nitrate (NaNO<sub>3</sub>). ==Nomenclature== In the 18th century, oxides were named '''calxes''' or '''calces''' after the [[calcination]] process used to produce oxides. ''Calx'' was later replaced by ''oxyd.'' <!--I think that calx is from the greek for ore, hence the term calcogen--> Oxides are usually named after the number of oxygen atoms in the oxide. Oxides containing only one oxygen are called oxides or [[mono-|monoxides]], those containing two oxygen atoms are [[di-|dioxides]], three oxygen atoms makes it a [[tri-|trioxide]], four oxygen atoms are [[tetra-|tetroxides]], and so on following the [[Greek language|Greek]] [[numerical prefix]]es. In the older literature and continuing in industry, oxides are named by contracting the element name with "a." Hence alumina, magnesia, chromia, are, respectively, Al<sub>2</sub>O<sub>3</sub>, MgO, Cr<sub>2</sub>O<sub>3</sub>. Two other types of oxide are [[peroxide]], O<sub>2</sub><sup>2−</sup>, and [[superoxide]], O<sub>2</sub><sup>−</sup>. In such species, oxygen is assigned higher [[oxidation state]]s than oxide. ==Types of oxides== Oxides of more [[electropositive]] elements tend to be basic. They are called '''basic anhydrides'''; adding water, they may form basic [[hydroxide]]s. For example, [[sodium oxide]] is basic; when hydrated, it forms [[sodium hydroxide]]. Oxides of more [[electronegative]] elements tend to be acidic. They are called '''acid anhydrides'''; adding water, they form [[oxoacid]]s. For example, [[dichlorine heptoxide]] is acid; [[perchloric acid]] is a more hydrated form. Some oxides can act as both acid and base at different times. They are [[amphoteric]]. An example is [[aluminium oxide]]. Some oxides do not show behavior as either acid or base. The oxides of the [[chemical element]]s in their highest [[oxidation state]] are predictable and the [[chemical formula]] can be derived from the number of [[valence electron]]s for that element. Even the chemical formula of O<sub>4</sub>, [[tetraoxygen]], is predictable as a [[group 16 element]]. One exception is [[copper]] for which the highest oxidation state oxide is [[copper(II) oxide]] and not [[copper(I) oxide]]. Another exception is [[fluoride]] that does not exist as expected as F<sub>2</sub>O<sub>7</sub> but as [[oxygen difluoride|OF<sub>2</sub>]] with the least [[electronegative]] element given priority. <ref>''Fully Exploiting the Potential of the Periodic Table through Pattern Recognition'' Schultz, Emeric. J. Chem. Educ. '''2005''' 82 1649.</ref>. [[Phosphorus pentoxide]], the third exception is not properly represented by the chemical formula [[Phosphorus|P]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub> but by [[Phosphorus|P]]<sub>4</sub>[[Oxygen|O]]<sub>10</sub> ==List of all known oxides sorted by oxidation state== {{Expand|date=December 2007}} <!-- an image with the periodic table showing all the known oxides should help--> * Element in −1 oxidation state ** [[Oxygen difluoride|Oxygen difluoride]] ([[Oxygen|O]][[Fluorine|F]]<sub>2</sub>) * Element in +1 oxidation state ** [[Copper(I) oxide]] ([[Copper|Cu]]<sub>2</sub>[[Oxygen|O]]) ** [[Dicarbon monoxide]] ([[Carbon|C]]<sub>2</sub>[[Oxygen|O]]) ** [[Dichlorine monoxide]] ([[Chlorine|Cl]]<sub>2</sub>[[Oxygen|O]]) ** [[Lithium oxide]] ([[Lithium|Li]]<sub>2</sub>[[Oxygen|O]]) ** [[Potassium oxide]] ([[Potassium|K]]<sub>2</sub>[[Oxygen|O]]) ** [[Rubidium oxide]] ([[Rubidium|Rb]]<sub>2</sub>[[Oxygen|O]]) ** [[Silver(I) oxide]] ([[Silver|Ag]]<sub>2</sub>[[Oxygen|O]]) ** [[Thallium oxide]] ([[Thallium|Tl]]<sub>2</sub>[[Oxygen|O]]) ** [[Sodium oxide]] ([[Sodium|Na]]<sub>2</sub>[[Oxygen|O]]) ** [[Water (molecule)|Water (hydrogen oxide)]] ([[Hydrogen|H]]<sub>2</sub>[[Oxygen|O]]) * Element in +2 oxidation state ** [[Aluminium monoxide]] ([[Aluminium|Al]][[Oxygen|O]]) ** [[Barium oxide]] ([[Barium|Ba]][[Oxygen|O]]) ** [[Beryllium oxide]] ([[Beryllium|Be]][[Oxygen|O]]) ** [[Cadmium oxide]] ([[Cadmium|Cd]][[Oxygen|O]]) ** [[Calcium oxide]] ([[Calcium|Ca]][[Oxygen|O]]) ** [[Carbon monoxide]] ([[Carbon|C]][[Oxygen|O]]) ** [[Cobalt(II) oxide]] ([[Cobalt|Co]][[Oxygen|O]]) ** [[Copper(II) oxide]] ([[Copper|Cu]][[Oxygen|O]]) ** [[Iron(II) oxide]] ([[Iron|Fe]][[Oxygen|O]]) ** [[Lead(II) oxide]] ([[Lead|Pb]][[Oxygen|O]]) ** [[Magnesium oxide]] ([[Magnesium|Mg]][[Oxygen|O]]) ** [[Mercury(II) oxide]] ({{mercury}}[[Oxygen|O]]) ** [[Nickel(II) oxide]] ([[Nickel|Ni]][[Oxygen|O]]) ** [[Nitrogen oxide]] ([[Nitrogen|N]][[Oxygen|O]]) ** [[Palladium(II) oxide]] ([[Paladium|Pd]][[Oxygen|O]]) ** [[Silver(II) oxide]] ([[Silver|Ag]][[Oxygen|O]]) ** [[Strontium oxide]] ([[Strontium|Sr]][[Oxygen|O]]) ** [[Sulphur monoxide]] ([[Sulfur|S]][[Oxygen|O]]) ** [[Tin(II) oxide]] ([[Tin|Sn]][[Oxygen|O]]) ** [[Titanium(II) oxide]] ([[Titanium|Ti]][[Oxygen|O]]) ** [[Vanadium(II) oxide]] ([[Vanadium|V]][[Oxygen|O]]) ** [[Zinc oxide]] ([[Zinc|Zn]][[Oxygen|O]]) * Element in +3 oxidation state ** [[Aluminium oxide]] ([[Aluminium|Al]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Antimony trioxide]] ([[Antimony|Sb]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Arsenic trioxide]] ([[Arsenic|As]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Bismuth trioxide]] ([[Bismuth|Bi]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Boron oxide]] ([[Boron|B]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Chromium(III) oxide]] ([[Chromium|Cr]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Dinitrogen trioxide]] ([[Nitrogen|N]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Erbium(III) oxide]] ([[Erbium|Er]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Gadolinium(III) oxide]] ([[Gadolinium|Gd]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Gallium(III) oxide]] ([[Gallium|Ga]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Holmium(III) oxide]] ([[Holmium|Ho]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Indium(III) oxide]] ([[Indium|In]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Iron(III) oxide]] ([[Iron|Fe]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Lanthanum(III) oxide]] ([[Lanthanum|La]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Lutetium(III) oxide]] ([[Lutetium|Lu]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Nickel(III) oxide]] ([[Nickel|Ni]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Phosphorus trioxide]] ([[Phosphorus|P]]<sub>4</sub>[[Oxygen|O]]<sub>6</sub>) ** [[Promethium(III) oxide]] ([[Promethium|Pm]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Rhodium(III) oxide]] ([[Rhodium|Rh]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Samarium(III) oxide]] ([[Samarium|Sm]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Scandium(III) oxide]] ([[Scandium|Sc]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Terbium(III) oxide]] ([[Terbium|Tb]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Thallium(III) oxide]] ([[Thallium|Tl]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Thulium(III) oxide]] ([[Thulium|Tm]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Titanium(III) oxide]] ([[Titanium|Ti]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Tungsten(III) oxide]] ([[Tungsten|W]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Vanadium(III) oxide]] ([[Vanadium|V]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Ytterbium(III) oxide]] ([[Ytterbium|Yb]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) ** [[Yttrium(III) oxide]] ([[Yttrium|Y]]<sub>2</sub>[[Oxygen|O]]<sub>3</sub>) * Element in +4 oxidation state ** [[Carbon dioxide]] ([[Carbon|C]][[Oxygen|O]]<sub>2</sub>) ** [[Carbon trioxide]] ([[Carbon|C]][[Oxygen|O]]<sub>3</sub>) ** [[Cerium(IV) oxide]] ([[Cerium|Ce]][[Oxygen|O]]<sub>2</sub>) ** [[Chlorine dioxide]] ([[Chlorine|Cl]][[Oxygen|O]]<sub>2</sub>) ** [[Chromium(IV) oxide]] ([[Chromium|Cr]][[Oxygen|O]]<sub>2</sub>) ** [[Dinitrogen tetroxide]] ([[Nitrogen|N]]<sub>2</sub>[[Oxygen|O]]<sub>4</sub>) ** [[Germanium dioxide]] ([[Germanium|Ge]][[Oxygen|O]]<sub>2</sub>) ** [[Hafnium(IV) oxide]] ([[Hafnium|Hf]][[Oxygen|O]]<sub>2</sub>) ** [[Lead(I) peroxide]] ([[Lead|Pb]][[Oxygen|O]]<sub>2</sub>) ** [[Manganese(IV) oxide]] ([[Manganese|Mn]][[Oxygen|O]]<sub>2</sub>) ** [[Nitrogen dioxide]] ([[Nitrogen|N]][[Oxygen|O]]<sub>2</sub>) ** [[Plutonium dioxide]] ([[Plutonium|Pu]][[Oxygen|O]]<sub>2</sub>) ** [[Ruthenium(IV) oxide]] ([[Ruthenium|Ru]][[Oxygen|O]]<sub>2</sub>) ** [[Selenium dioxide]] ([[Selenium|Se]][[Oxygen|O]]<sub>2</sub>) ** [[Silicon dioxide]] ([[Silicon|Si]][[Oxygen|O]]<sub>2</sub>) ** [[Sulfur dioxide]] ([[Sulfur|S]][[Oxygen|O]]<sub>2</sub>) ** [[Tellurium dioxide]] ([[Tellurium|Te]][[Oxygen|O]]<sub>2</sub>) ** [[Thorium dioxide]] ({{thorium}}[[Oxygen|O]]<sub>2</sub>) ** [[Tin dioxide]] ([[Tin|Sn]][[Oxygen|O]]<sub>2</sub>) ** [[Titanium dioxide]] ([[Titanium|Ti]][[Oxygen|O]]<sub>2</sub>) ** [[Tungsten(IV) oxide]] ([[Tungsten|W]][[Oxygen|O]]<sub>2</sub>) ** [[Uranium dioxide]] ([[Uranium|U]][[Oxygen|O]]<sub>2</sub>) ** [[Vanadium(IV) oxide]] ([[Vanadium|V]][[Oxygen|O]]<sub>2</sub>) ** [[Zirconium dioxide]] ([[Zirconium|Zr]][[Oxygen|O]]<sub>2</sub>) * Element in +5 oxidation state ** [[Antimony pentoxide]] ([[Antimony|Sb]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) ** [[Arsenic pentoxide]] ([[Arsenic|As]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) ** [[Dinitrogen pentoxide]] ([[Nitrogen|N]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) ** [[Niobium pentoxide]] ** [[Phosphorus pentoxide]] ([[Phosphorus|P]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) ** [[Tantalum pentoxide]] ([[Tantalum|Ta]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) ** [[Vanadium(V) oxide]] ([[Vanadium|V]]<sub>2</sub>[[Oxygen|O]]<sub>5</sub>) * Element in +6 oxidation state ** [[Chromium trioxide]] ([[Chromium|Cr]][[Oxygen|O]]<sub>3</sub>) ** [[Molybdenum(VI) oxide]] ([[Molybdenum|Mo]][[Oxygen|O]]<sub>3</sub>) ** [[Rhenium trioxide]] ([[Rhenium|Re]][[Oxygen|O]]<sub>3</sub>) ** [[Selenium trioxide]] ([[Selenium|Se]][[Oxygen|O]]<sub>3</sub>) ** [[Sulphur trioxide]] ([[Sulfur|S]][[Oxygen|O]]<sub>3</sub>) ** [[Tellurium trioxide]] ([[Tellurium|Te]][[Oxygen|O]]<sub>3</sub>) ** [[Tungsten trioxide]] ([[Tungsten|W]][[Oxygen|O]]<sub>3</sub>) ** [[Uranium trioxide]] ([[Uranium|U]][[Oxygen|O]]<sub>3</sub>) ** [[Xenon trioxide]] ([[Xenon|Xe]][[Oxygen|O]]<sub>3</sub>) * Element in +7 oxidation state ** [[Dichlorine heptoxide]] ([[Chlorine|Cl]]<sub>2</sub>[[Oxygen|O]]<sub>7</sub>) ** [[Manganese(VII) oxide]] ([[Manganese|Mn]]<sub>2</sub>[[Oxygen|O]]<sub>7</sub>) ** [[Rhenium(VII) oxide]] ([[Rhenium|Re]]<sub>2</sub>[[Oxygen|O]]<sub>7</sub>) ** [[Technetium(VII) oxide]] * Element in +8 oxidation state ** [[Osmium tetroxide]] ([[Osmium|Os]][[Oxygen|O]]<sub>4</sub>) ** [[Ruthenium tetroxide]] ([[Ruthenium|Ru]][[Oxygen|O]]<sub>4</sub>) ** [[Xenon tetroxide]] ([[Xenon|Xe]][[Oxygen|O]]<sub>4</sub>) == See also == {{Wiktionary}} * Other oxygen ions [[ozonide]], O<sub>3</sub><sup>−</sup>, [[superoxide]], O<sub>2</sub><sup>−</sup>, [[peroxide]], O<sub>2</sub><sup>2−</sup> and [[dioxygenyl]], O<sub>2</sub><sup>+</sup>. * [[Suboxide]] * See [[:Category:Oxides]] for a list of oxides. == References == <references /> [[Category:Oxides|*]] [[ar:أكسيد]] [[ast:Óxidu]] [[bs:Oksidi]] [[bg:Оксид]] [[ca:Òxid]] [[cs:Oxid]] [[da:Oxid]] [[de:Oxide]] [[et:Oksiidid]] [[el:Οξείδιο]] [[es:Óxido]] [[eo:Oksido]] [[fr:Oxyde]] [[gl:Óxido]] [[hr:Oksidi]] [[id:Oksida]] [[it:Ossido]] [[he:תחמוצת]] [[la:Oxidum]] [[lv:Oksīds]] [[lt:Oksidas]] [[mk:Оксид]] [[nl:Oxide]] [[ja:酸化物]] [[no:Oksid]] [[nn:Oksid]] [[uz:Oksid]] [[nds:Oxid]] [[pl:Tlenki]] [[pt:Óxido]] [[ro:Oxid]] [[qu:Muksi]] [[ru:Оксиды]] [[simple:Oxide]] [[sk:Oxid]] [[sl:Oksid]] [[sr:Оксид]] [[sh:Oksid]] [[fi:Oksidi]] [[sv:Oxider]] [[th:ออกไซด์]] [[vi:Ôxít]] [[tr:Oksit]] [[uk:Оксид]] [[zh:氧化物]]