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{{Short description|Oxide compound with cations of multiple elements or different oxidation states}}
{{for|nuclear reactor fuel|MOX fuel}}
{{See also|Complex oxide}}
{{For|nuclear reactor fuel|MOX fuel}}


In [[chemistry]], a '''mixed oxide''' is a somewhat informal name for an [[oxide]] that contains more than one [[chemical element]] in its cation, or of a single element cation that has atoms in several states of [[oxidation]].
In [[chemistry]], a '''mixed oxide''' is a somewhat informal name for an [[oxide]] that contains cations of more than one [[chemical element]] or cations of a single element in several [[Oxidation state|states of oxidation]].<ref name = "Cotton-2dEd">Advanced Inorganic Chemistry, [[F. Albert Cotton|F. A. Cotton]], G. Wilkinson, Interscience, 2d Edition, 1966</ref>


The term is usually applied to solid [[ionic compounds]] that contain the oxide [[anion]] O<sup>2&minus;</sup> and two or more element [[cation]]s. A typical example is the mineral [[ilmenite]] (FeTiO<sub>3</sub>), a mixed oxide of [[iron]] (Fe<sup>2+</sup>) and [[titanium]] (Ti<sup>4+</sup>) cations. The cations may be the same element in different ionization states: a notable example is [[magnetite]] Fe<sub>3</sub>O<sub>4</sub>, which contains the cations Fe<sup>2+</sup> ("ferrous" iron) and Fe<sup>3+</sup> ("ferric" iron) in 1:1 ratio. Other notable examples include the [[ferrite (magnet)|ferrite]]s,<ref name="gman">Alex Goldman (1990), ''Modern ferrite technology''</ref> [[strontium titanate]] SrTiO<sub>3</sub> (which, despite its name, contains Ti<sup>4+</sup> cations and not the TiO<sub>3</sub><sup>2-</sup> anion), [[yttrium aluminum garnet]] Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>,<ref>K. Byrappa, Masahiro Yoshimura (2001), ''Handbook of hydrothermal technology''. William Andrew. 870 pages.</ref> and many more.
The term is usually applied to solid [[ionic compound]]s that contain the oxide [[anion]] {{chem2|O(2−)}} and two or more element [[cation]]s. Typical examples are [[ilmenite]] ({{chem2|FeTiO3}}), a mixed oxide of [[iron]] ({{chem2|Fe(2+)}}) and [[titanium]] ({{chem2|Ti(4+)}}) cations, [[perovskite]] and [[garnet]].The cations may be the same element in different ionization states: a notable example is [[magnetite]] {{chem2|Fe3O4}}, which is also known as ferrosoferric oxide , contains the cations {{chem2|Fe(2+)}} ("ferrous" iron) and {{chem2|Fe(3+)}} ("ferric" iron) in 1:2 ratio. Other notable examples include [[lead(II,IV) oxide|red lead]] {{chem2|Pb3O4}}, the [[ferrite (magnet)|ferrite]]s,<ref name="gman">Alex Goldman (1990), ''Modern ferrite technology''</ref> and the [[yttrium aluminum garnet]] {{chem2|Y3Al5O12}},<ref>K. Byrappa, Masahiro Yoshimura (2001), ''Handbook of hydrothermal technology''. William Andrew. 870 pages.</ref> used in [[laser]]s.


The term is sometimes also applied to compounds of oxygen and two or more other elements, where some or all of the oxygen atoms are covalently bound into [[oxyanion]]s. In [[sodium zincate]] {{chem2|Na2ZnO2}}, for example, the oxygens are bound to the [[zinc]] atoms forming [[zincate]] anions.<ref name=trin1996>D. Trinschek, M. Jansen (1996): "{{chem2|Na2ZnO2}}, ein neues Natriumzinkat". ''Zeitschrift für Naturforschung B'', volume 51, issue 5, pages 711-714. {{doi|10.1515/znb-1996-0515}}</ref> (On the other hand, [[strontium titanate]] {{chem2|SrTiO3}}, despite its name, contains {{chem2|Ti(4+)}} cations and not the {{chem2|TiO3(2−)}} anion.)
Mixed oxides are intermediate between a metal oxide and a metal salt. Sometimes mixed oxides are the salts of weak metallic acids. Most other times they are just two different oxides that bond together strongly.


Sometimes the term is applied loosely to [[solid solution]]s of metal oxides rather than chemical compounds, or to fine mixtures of two or more oxides.
However, the term is sometimes also applied to compounds of oxygen and two or more other elements, where some or all of the oxygen atoms are covalently bound into [[oxoanion]]s.{{clarify|date=June 2009}}{{fact|date=June 2009}}; or to fine mixtures of two or more oxides. An example would be the [[zincate]]s. Zinc hydroxide can react with concentrated sodium hydroxide to become sodium zincate. This contains zincate ions.


Mixed oxide minerals are plentiful in nature. Synthetic mixed oxides are components of many ceramics with remarkable properties and important advanced technological applications, such as strong [[magnet]]s, fine [[optics]], [[laser]]s, [[semiconductor]]s, [[piezoelectric]]s, [[superconductor]]s, [[catalyst]]s, [[refractory|refractories]], [[gas mantle]]s, [[MOX fuel|nuclear fuel]]s, and more. Piezoelectric mixed oxides, in particular, are extensively used in [[pressure gauge|pressure]] and [[strain gauge]]s, [[microphone]]s, [[ultrasound]] [[transducer]]s, [[micromanipulator]]s, [[delay line]]s, etc..
Mixed oxide minerals are plentiful in nature. Synthetic mixed oxides are components of many ceramics with remarkable properties and important advanced technological applications, such as strong [[magnet]]s, fine [[optics]], [[laser]]s, [[semiconductor]]s, [[piezoelectric]]s, [[superconductor]]s, [[catalyst]]s, [[refractory|refractories]], [[gas mantle]]s, [[MOX fuel|nuclear fuel]]s, and more. Piezoelectric mixed oxides, in particular, are extensively used in [[pressure gauge|pressure]] and [[strain gauge]]s, [[microphone]]s, [[ultrasound]] [[transducer]]s, [[micromanipulator]]s, [[Analog delay line|delay lines]], etc.

==See also==
* [[Complex oxide]]
* [[Double salt]]
* [[MOX fuel]]


==References==
==References==
{{reflist}}
{{reflist}}


[[Category:Oxides]]
[[Category:Oxides| ]]



{{inorganic-compound-stub}}
{{inorganic-compound-stub}}

Latest revision as of 11:45, 8 December 2023

In chemistry, a mixed oxide is a somewhat informal name for an oxide that contains cations of more than one chemical element or cations of a single element in several states of oxidation.[1]

The term is usually applied to solid ionic compounds that contain the oxide anion O2− and two or more element cations. Typical examples are ilmenite (FeTiO3), a mixed oxide of iron (Fe2+) and titanium (Ti4+) cations, perovskite and garnet.The cations may be the same element in different ionization states: a notable example is magnetite Fe3O4, which is also known as ferrosoferric oxide , contains the cations Fe2+ ("ferrous" iron) and Fe3+ ("ferric" iron) in 1:2 ratio. Other notable examples include red lead Pb3O4, the ferrites,[2] and the yttrium aluminum garnet Y3Al5O12,[3] used in lasers.

The term is sometimes also applied to compounds of oxygen and two or more other elements, where some or all of the oxygen atoms are covalently bound into oxyanions. In sodium zincate Na2ZnO2, for example, the oxygens are bound to the zinc atoms forming zincate anions.[4] (On the other hand, strontium titanate SrTiO3, despite its name, contains Ti4+ cations and not the TiO2−3 anion.)

Sometimes the term is applied loosely to solid solutions of metal oxides rather than chemical compounds, or to fine mixtures of two or more oxides.

Mixed oxide minerals are plentiful in nature. Synthetic mixed oxides are components of many ceramics with remarkable properties and important advanced technological applications, such as strong magnets, fine optics, lasers, semiconductors, piezoelectrics, superconductors, catalysts, refractories, gas mantles, nuclear fuels, and more. Piezoelectric mixed oxides, in particular, are extensively used in pressure and strain gauges, microphones, ultrasound transducers, micromanipulators, delay lines, etc.

See also

[edit]

References

[edit]
  1. ^ Advanced Inorganic Chemistry, F. A. Cotton, G. Wilkinson, Interscience, 2d Edition, 1966
  2. ^ Alex Goldman (1990), Modern ferrite technology
  3. ^ K. Byrappa, Masahiro Yoshimura (2001), Handbook of hydrothermal technology. William Andrew. 870 pages.
  4. ^ D. Trinschek, M. Jansen (1996): "Na2ZnO2, ein neues Natriumzinkat". Zeitschrift für Naturforschung B, volume 51, issue 5, pages 711-714. doi:10.1515/znb-1996-0515