Difference between revisions of "Hydride" - New World Encyclopedia
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| − | {{ | + | {{Images OK}}{{Submitted}}{{Approved}}{{Paid}}{{Copyedited}} |
| − | [[Image:Lialh4 sem.png|thumb|Lithium aluminum hydride (LiAlH<sub>4</sub>) powder, as observed with a scanning electron microscope.]] | + | [[Image:Lialh4 sem.png|thumb|200px|Lithium aluminum hydride (LiAlH<sub>4</sub>) powder, as observed with a scanning electron microscope.]] |
| − | ''' | + | The name '''hydride''' is used for the [[Electric charge|negative]] [[ion]] of [[hydrogen]], H<sup>−</sup>, and for [[Chemical compound|compounds]] of hydrogen with other [[chemical element|elements]]. Every element of the [[periodic table]] (except some [[noble gas]]es) forms one or more compounds with hydrogen, and these compounds (especially those with elements in groups 1–15 of the periodic table) may be referred to as hydrides. Thus, the term "hydride" can be used very broadly. These compounds may be classified into three main types: ''saline (ionic) hydrides'', ''covalent hydrides'', and ''interstitial hydrides''. The hydrides are called ''binary'' if they involve only two elements including hydrogen. |
| − | + | {{toc}} | |
| − | + | Hydrides are useful for a wide diversity of applications. For instance, [[sodium hydride]] is a strong base used in organic chemistry; [[lithium aluminum hydride]] and [[sodium borohydride]] are reducing agents in chemical reactions; [[nickel hydride]] is found in [[nickel]] metal hydride batteries; and hydrides with [[arsenic]] and [[antimony]] ([[arsine]] and [[stibine]]) are used in the semiconductor industry. In addition, [[silane]] is used for the manufacture of [[composite material]]s, and [[diborane]] is a rocket fuel, semiconductor dopant, and reducing agent. Also, various metal hydrides are being studied for possible hydrogen storage in [[fuel cell]]-powered electric cars and [[Battery (electricity)|batteries]]. | |
| − | |||
== Hydride ion == | == Hydride ion == | ||
| − | Aside from [[electride]], the hydride ion is the simplest possible [[anion]], consisting of two [[electron]]s and a [[proton]]. Hydrogen has a relatively low [[electron affinity]], 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. The reactivity of the | + | Aside from [[electride]]s,<ref>An electride is an [[ion]]ic compound in which an [[electron]] is the anion.</ref> the hydride ion is the simplest possible [[anion]], consisting of two [[electron]]s and a [[proton]]. However, the free hydride ion is so unstable that it exists only under exceptional conditions. |
| + | |||
| + | Hydrogen has a relatively low [[electron affinity]], 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. The reactivity of the hypothetical hydride ion is dominated by its exothermic protonation to give [[dihydrogen]]: | ||
::H<sup>−</sup> + H<sup>+</sup> → H<sub>2</sub>; [[Enthalpy|Δ''H'']] = −1675 kJ/mol | ::H<sup>−</sup> + H<sup>+</sup> → H<sub>2</sub>; [[Enthalpy|Δ''H'']] = −1675 kJ/mol | ||
As a result, the hydride ion is one of the strongest [[base (chemistry)|base]]s known. It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong [[reducing agent]]: | As a result, the hydride ion is one of the strongest [[base (chemistry)|base]]s known. It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong [[reducing agent]]: | ||
::H<sub>2</sub> + 2e<sup>−</sup> {{unicode|⇌}} 2H<sup>−</sup>; [[Standard electrode potential|''E''<sup><s>o</s></sup>]] = −2.25 V | ::H<sub>2</sub> + 2e<sup>−</sup> {{unicode|⇌}} 2H<sup>−</sup>; [[Standard electrode potential|''E''<sup><s>o</s></sup>]] = −2.25 V | ||
| − | == | + | == Compounds known as "hydrides" == |
| − | + | ||
| + | The compounds known as "hydrides" are classified according to the predominant nature of their [[Chemical bond|bonding]]: | ||
| + | *''Saline (ionic) hydrides'', which have significant ionic character; | ||
| + | *''Covalent hydrides'', which include the hydrocarbons and many other compounds; and | ||
| + | *''Interstitial hydrides'', which may be described as having [[metallic bonding]]. | ||
| + | |||
| + | === Saline (ionic) hydrides === | ||
| + | |||
| + | Saline (or ionic) hydrides are ionic compounds, and therefore salt-like. They are solids with high [[melting point]]s. In these cases, hydrogen is in the form of the [[anion]] (H<sup>−</sup>), which is combined with a highly [[electronegativity|electropositive]] element, usually one of the [[alkali metal]]s or some of the [[alkaline earth metal]]s ([[calcium]], [[strontium]], [[barium]]). Examples are sodium hydride (NaH) and calcium hydride (CaH<sub>2</sub>). | ||
| + | |||
| + | In each ionic hydride, the hydrogen atom behaves as a [[halogen]] atom, obtaining an [[electron]] from the [[metal]] atom to form a hydride ion (H<sup>−</sup>). The hydrogen atom thereby fills its 1s-orbital and attaining the stable [[electron configuration]] of [[helium]]. | ||
| + | |||
| + | If the metal is less electropositive, the metal-hydrogen bond becomes more covalent. Examples are [[magnesium|Mg]]H<sub>2</sub> and [[aluminium|Al]]H<sub>3</sub>. | ||
| + | |||
| + | Ionic hydrides are commonly encountered as basic [[reagent]]s in [[organic synthesis]]: | ||
:[[Acetophenone|C<sub>6</sub>H<sub>5</sub>C(O)CH<sub>3</sub>]] + [[Potassium hydride|KH]] → C<sub>6</sub>H<sub>5</sub>C(O)CH<sub>2</sub>K + H<sub>2</sub> | :[[Acetophenone|C<sub>6</sub>H<sub>5</sub>C(O)CH<sub>3</sub>]] + [[Potassium hydride|KH]] → C<sub>6</sub>H<sub>5</sub>C(O)CH<sub>2</sub>K + H<sub>2</sub> | ||
| − | Such reactions are heterogeneous, the KH does not dissolve. Typical solvents for such reactions are [[ether]]s. | + | Such reactions are heterogeneous, the KH does not dissolve. Typical solvents for such reactions are [[ether]]s. |
| + | |||
| + | [[Water]] cannot serve as a medium for pure ionic hydrides because the hydride ion is a stronger [[Base (chemistry)|base]] than [[hydroxide]]. Hydrogen gas is liberated in a typical acid-base reaction. | ||
:NaH + H<sub>2</sub>[[Oxygen|O]] → H<sub>2</sub> (gas) + NaOH Δ''H'' = −83.6 kJ/mol, [[Gibbs free energy|Δ''G'']] = −109.0 kJ/mol | :NaH + H<sub>2</sub>[[Oxygen|O]] → H<sub>2</sub> (gas) + NaOH Δ''H'' = −83.6 kJ/mol, [[Gibbs free energy|Δ''G'']] = −109.0 kJ/mol | ||
| − | Alkali metal hydrides react with metal halides. | + | Alkali metal hydrides react with metal halides. For example, [[lithium aluminum hydride]] (often abbreviated as LAH) arises from reactions with [[aluminum chloride]]. |
:4 [[Lithium hydride|LiH]] + AlCl<sub>3</sub> → LiAlH<sub>4</sub> + 3 LiCl | :4 [[Lithium hydride|LiH]] + AlCl<sub>3</sub> → LiAlH<sub>4</sub> + 3 LiCl | ||
| − | ==Covalent hydrides== | + | ===Covalent hydrides=== |
| − | |||
| − | + | In covalent hydrides, hydrogen is [[covalent bond|covalently bonded]] to an element in the p-block of the periodic table ([[boron]], [[aluminum]], and elements in groups 14-17), as well as [[beryllium]]. The [[hydrocarbon]]s and [[ammonia]] could be considered ''hydrides'' of [[carbon]] and [[nitrogen]], respectively. | |
| − | |||
| − | + | Charge-neutral covalent hydrides that are made up of small molecules are often volatile at room temperature and [[atmospheric pressure]]. Some covalent hydrides are not volatile because they are polymeric (i.e., nonmolecular), such as the binary hydrides of aluminum and beryllium. Replacing some hydrogen atoms in such compounds with larger [[ligand]]s, one obtains molecular derivatives. For example, [[diisobutylaluminum hydride]] (DIBAL) consists of two aluminum centers bridged by hydride ligands. | |
| − | |||
| − | Interstitial hydrides show | + | Hydrides that are soluble in common solvents are widely used in [[organic synthesis]]. Particularly common are [[sodium borohydride]] (NaBH<sub>4</sub>) and [[lithium]] [[aluminum]] hydride. |
| + | |||
| + | ===Interstitial hydrides of transition metals=== | ||
| + | |||
| + | Transition metals form binary hydrides in which hydrogen atoms are bonded to the metal atoms, but the exact nature of those bonds is not clear. In addition, the ratio of hydrogen atoms to metal atoms in a number of these hydrides is not fixed. The lattice of metal atoms contains a variable number of hydrogen atoms that can migrate through it. In [[materials engineering]], the phenomenon of [[hydrogen embrittlement]] is a consequence of interstitial hydrides. | ||
| + | |||
| + | For example, [[palladium]] absorbs up to 900 times its own volume of hydrogen at room temperature, forming [[palladium hydride]], which was once thought of as a means to carry hydrogen for vehicular [[fuel cell]]s. Hydrogen gas is liberated proportional to the applied temperature and pressure but not to the chemical composition. | ||
| + | |||
| + | Interstitial hydrides show some promise as a way for safe hydrogen storage. During the last 25 years, many interstitial hydrides were developed that readily absorb and discharge hydrogen at room temperature and atmospheric pressure. They are usually based on [[intermetallic]] compounds and solid-solution alloys. However, their application is still limited, as they are capable of storing only about 2 percent (by weight) of hydrogen, which is not enough for automotive applications. | ||
| + | |||
| + | ==Transition metal hydride (or hydrido) complexes== | ||
| + | |||
| + | Most transition [[metal complex]]es form molecular compounds described as hydrides. Usually, such compounds are discussed in the context of [[organometallic chemistry]]. Transition metal hydrides are intermediates in many industrial processes that rely on metal catalysts, such as [[hydroformylation]], [[hydrogenation]], and [[hydrodesulfurization]]. Two famous examples, HCo(CO)<sub>4</sub> and H<sub>2</sub>Fe(CO)<sub>4</sub>, are acidic, thus demonstrating that the term hydride is used very broadly. | ||
| + | |||
| + | When a [[dihydrogen complex]] loses a proton, a metal hydride is produced. The anion [[Potassium nonahydridorhenate|[ReH<sub>9</sub>]<sup>2-</sup>]] (nonahydridorhenate) is an example of a molecular metal hydride. | ||
==Nomenclature== | ==Nomenclature== | ||
| − | + | ||
| − | The following | + | The following list gives the nomenclature for hydrides of main group elements: |
*[[alkali metal|alkali]] and [[alkaline earth metal|alkaline earth]] metals: metal hydride | *[[alkali metal|alkali]] and [[alkaline earth metal|alkaline earth]] metals: metal hydride | ||
*[[boron]]: [[borane]] and rest of the group as metal hydride | *[[boron]]: [[borane]] and rest of the group as metal hydride | ||
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*[[bismuth]]: [[bismuthine]] ('bismuthane' when substituted) | *[[bismuth]]: [[bismuthine]] ('bismuthane' when substituted) | ||
| − | According to the convention above, the following | + | According to the convention used above, the following elements form "hydrogen compounds" and not "hydrides": |
*[[oxygen]]: [[water]] ('oxidane' when substituted), [[hydrogen peroxide]] | *[[oxygen]]: [[water]] ('oxidane' when substituted), [[hydrogen peroxide]] | ||
*[[sulfur]]: [[hydrogen sulfide]] ('sulfane' when substituted) | *[[sulfur]]: [[hydrogen sulfide]] ('sulfane' when substituted) | ||
| Line 57: | Line 85: | ||
*[[halogen]]s: hydrogen halides | *[[halogen]]s: hydrogen halides | ||
| − | + | ===Isotopes of hydride=== | |
| + | |||
| + | ''Protide'', ''deuteride'', and ''tritide'' are used to describe ions or compounds, which contain [[isotopic enrichment|enriched]] [[hydrogen-1]], [[deuterium]] or [[tritium]], respectively. | ||
| + | |||
| + | ===Precedence convention=== | ||
| + | |||
| + | According to [[IUPAC inorganic nomenclature|IUPAC convention]], by precedence (stylized electronegativity), hydrogen falls between [[nitrogen group|group 15]] and [[chalcogen|group 16]] elements. Therefore we have NH<sub>3</sub>, 'nitrogen hydride' ([[ammonia]]), versus H<sub>2</sub>O, 'hydrogen oxide' ([[water]]). | ||
| + | |||
| + | == Uses == | ||
| + | |||
| + | Various metal hydrides are currently being studied for use as a means of hydrogen storage in [[fuel cell]]-powered electric cars and [[Battery (electricity)|batteries]]. They also have important uses in [[organic chemistry]] as powerful [[reducing agent]]s, and many promising uses in the proposed [[hydrogen economy]]. | ||
| + | |||
| + | The names and uses of some specific hydrides are given below: | ||
*[[nickel hydride]]: used in [[NiMH battery|NiMH batteries]] | *[[nickel hydride]]: used in [[NiMH battery|NiMH batteries]] | ||
| − | *[[palladium hydride]]: electrodes in [[cold fusion]] experiments | + | *[[palladium hydride]]: catalyst in organic reactions; electrodes in [[cold fusion]] experiments |
| − | *[[lithium | + | *[[lithium aluminum hydride]]: a powerful reducing agent used in organic chemistry |
*[[sodium borohydride]]: selective specialty reducing agent, hydrogen storage in [[direct borohydride fuel cell|fuel cells]] | *[[sodium borohydride]]: selective specialty reducing agent, hydrogen storage in [[direct borohydride fuel cell|fuel cells]] | ||
*[[sodium hydride]]: a powerful base used in organic chemistry | *[[sodium hydride]]: a powerful base used in organic chemistry | ||
| Line 69: | Line 109: | ||
*[[silane]]: many industrial uses, e.g. manufacture of [[composite material]]s and water repellents | *[[silane]]: many industrial uses, e.g. manufacture of [[composite material]]s and water repellents | ||
*[[ammonia]]: [[coolant]], [[fertilizer]], many other industrial uses | *[[ammonia]]: [[coolant]], [[fertilizer]], many other industrial uses | ||
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==See also== | ==See also== | ||
| Line 82: | Line 114: | ||
* [[Ammonia]] | * [[Ammonia]] | ||
* [[Hydrogen]] | * [[Hydrogen]] | ||
| + | |||
| + | == Notes == | ||
| + | <references/> | ||
== References == | == References == | ||
| − | + | * Brown Jr., Theodore L., H. Eugene LeMay, Bruce Edward Bursten, and Julia R. Burdge. 2002. ''Chemistry: The Central Science''. 9th ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0130669970. | |
| + | |||
| + | * Chang, Raymond. 2006. ''Chemistry,'' 9th ed. New York: McGraw-Hill Science/Engineering/Math. ISBN 0073221031. | ||
| + | |||
| + | * Cotton, F. Albert, and Geoffrey Wilkinson. 1980. ''Advanced Inorganic Chemistry,'' 4th ed. New York: Wiley. ISBN 0471027758. | ||
| + | |||
| + | * McMurry, J., and R.C. Fay. 2004. ''Chemistry,'' 4th ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0131402080. | ||
| − | |||
[[Category:Physical sciences]] | [[Category:Physical sciences]] | ||
Latest revision as of 15:22, 29 March 2014
The name hydride is used for the negative ion of hydrogen, H−, and for compounds of hydrogen with other elements. Every element of the periodic table (except some noble gases) forms one or more compounds with hydrogen, and these compounds (especially those with elements in groups 1–15 of the periodic table) may be referred to as hydrides. Thus, the term "hydride" can be used very broadly. These compounds may be classified into three main types: saline (ionic) hydrides, covalent hydrides, and interstitial hydrides. The hydrides are called binary if they involve only two elements including hydrogen.
Hydrides are useful for a wide diversity of applications. For instance, sodium hydride is a strong base used in organic chemistry; lithium aluminum hydride and sodium borohydride are reducing agents in chemical reactions; nickel hydride is found in nickel metal hydride batteries; and hydrides with arsenic and antimony (arsine and stibine) are used in the semiconductor industry. In addition, silane is used for the manufacture of composite materials, and diborane is a rocket fuel, semiconductor dopant, and reducing agent. Also, various metal hydrides are being studied for possible hydrogen storage in fuel cell-powered electric cars and batteries.
Hydride ion
Aside from electrides,[1] the hydride ion is the simplest possible anion, consisting of two electrons and a proton. However, the free hydride ion is so unstable that it exists only under exceptional conditions.
Hydrogen has a relatively low electron affinity, 72.77 kJ/mol, thus hydride is so basic that it is unknown in solution. The reactivity of the hypothetical hydride ion is dominated by its exothermic protonation to give dihydrogen:
- H− + H+ → H2; ΔH = −1675 kJ/mol
As a result, the hydride ion is one of the strongest bases known. It would extract protons from almost any hydrogen-containing species. The low electron affinity of hydrogen and the strength of the H–H bond (436 kJ/mol) means that the hydride ion would also be a strong reducing agent:
- H2 + 2e− ⇌ 2H−; E
o= −2.25 V
- H2 + 2e− ⇌ 2H−; E
Compounds known as "hydrides"
The compounds known as "hydrides" are classified according to the predominant nature of their bonding:
- Saline (ionic) hydrides, which have significant ionic character;
- Covalent hydrides, which include the hydrocarbons and many other compounds; and
- Interstitial hydrides, which may be described as having metallic bonding.
Saline (ionic) hydrides
Saline (or ionic) hydrides are ionic compounds, and therefore salt-like. They are solids with high melting points. In these cases, hydrogen is in the form of the anion (H−), which is combined with a highly electropositive element, usually one of the alkali metals or some of the alkaline earth metals (calcium, strontium, barium). Examples are sodium hydride (NaH) and calcium hydride (CaH2).
In each ionic hydride, the hydrogen atom behaves as a halogen atom, obtaining an electron from the metal atom to form a hydride ion (H−). The hydrogen atom thereby fills its 1s-orbital and attaining the stable electron configuration of helium.
If the metal is less electropositive, the metal-hydrogen bond becomes more covalent. Examples are MgH2 and AlH3.
Ionic hydrides are commonly encountered as basic reagents in organic synthesis:
- C6H5C(O)CH3 + KH → C6H5C(O)CH2K + H2
Such reactions are heterogeneous, the KH does not dissolve. Typical solvents for such reactions are ethers.
Water cannot serve as a medium for pure ionic hydrides because the hydride ion is a stronger base than hydroxide. Hydrogen gas is liberated in a typical acid-base reaction.
Alkali metal hydrides react with metal halides. For example, lithium aluminum hydride (often abbreviated as LAH) arises from reactions with aluminum chloride.
- 4 LiH + AlCl3 → LiAlH4 + 3 LiCl
Covalent hydrides
In covalent hydrides, hydrogen is covalently bonded to an element in the p-block of the periodic table (boron, aluminum, and elements in groups 14-17), as well as beryllium. The hydrocarbons and ammonia could be considered hydrides of carbon and nitrogen, respectively.
Charge-neutral covalent hydrides that are made up of small molecules are often volatile at room temperature and atmospheric pressure. Some covalent hydrides are not volatile because they are polymeric (i.e., nonmolecular), such as the binary hydrides of aluminum and beryllium. Replacing some hydrogen atoms in such compounds with larger ligands, one obtains molecular derivatives. For example, diisobutylaluminum hydride (DIBAL) consists of two aluminum centers bridged by hydride ligands.
Hydrides that are soluble in common solvents are widely used in organic synthesis. Particularly common are sodium borohydride (NaBH4) and lithium aluminum hydride.
Interstitial hydrides of transition metals
Transition metals form binary hydrides in which hydrogen atoms are bonded to the metal atoms, but the exact nature of those bonds is not clear. In addition, the ratio of hydrogen atoms to metal atoms in a number of these hydrides is not fixed. The lattice of metal atoms contains a variable number of hydrogen atoms that can migrate through it. In materials engineering, the phenomenon of hydrogen embrittlement is a consequence of interstitial hydrides.
For example, palladium absorbs up to 900 times its own volume of hydrogen at room temperature, forming palladium hydride, which was once thought of as a means to carry hydrogen for vehicular fuel cells. Hydrogen gas is liberated proportional to the applied temperature and pressure but not to the chemical composition.
Interstitial hydrides show some promise as a way for safe hydrogen storage. During the last 25 years, many interstitial hydrides were developed that readily absorb and discharge hydrogen at room temperature and atmospheric pressure. They are usually based on intermetallic compounds and solid-solution alloys. However, their application is still limited, as they are capable of storing only about 2 percent (by weight) of hydrogen, which is not enough for automotive applications.
Transition metal hydride (or hydrido) complexes
Most transition metal complexes form molecular compounds described as hydrides. Usually, such compounds are discussed in the context of organometallic chemistry. Transition metal hydrides are intermediates in many industrial processes that rely on metal catalysts, such as hydroformylation, hydrogenation, and hydrodesulfurization. Two famous examples, HCo(CO)4 and H2Fe(CO)4, are acidic, thus demonstrating that the term hydride is used very broadly.
When a dihydrogen complex loses a proton, a metal hydride is produced. The anion [ReH9]2- (nonahydridorhenate) is an example of a molecular metal hydride.
Nomenclature
The following list gives the nomenclature for hydrides of main group elements:
- alkali and alkaline earth metals: metal hydride
- boron: borane and rest of the group as metal hydride
- carbon: alkanes, alkenes, alkynes, and all hydrocarbons
- silicon: silane
- germanium: germane
- tin: stannane
- lead: plumbane
- nitrogen: ammonia ('azane' when substituted), hydrazine
- phosphorus: phosphine ('phosphane' when substituted)
- arsenic: arsine ('arsane' when substituted)
- antimony: stibine ('stibane' when substituted)
- bismuth: bismuthine ('bismuthane' when substituted)
According to the convention used above, the following elements form "hydrogen compounds" and not "hydrides":
- oxygen: water ('oxidane' when substituted), hydrogen peroxide
- sulfur: hydrogen sulfide ('sulfane' when substituted)
- selenium: hydrogen selenide ('selane' when substituted)
- tellurium: hydrogen telluride ('tellane' when substituted)
- halogens: hydrogen halides
Isotopes of hydride
Protide, deuteride, and tritide are used to describe ions or compounds, which contain enriched hydrogen-1, deuterium or tritium, respectively.
Precedence convention
According to IUPAC convention, by precedence (stylized electronegativity), hydrogen falls between group 15 and group 16 elements. Therefore we have NH3, 'nitrogen hydride' (ammonia), versus H2O, 'hydrogen oxide' (water).
Uses
Various metal hydrides are currently being studied for use as a means of hydrogen storage in fuel cell-powered electric cars and batteries. They also have important uses in organic chemistry as powerful reducing agents, and many promising uses in the proposed hydrogen economy.
The names and uses of some specific hydrides are given below:
- nickel hydride: used in NiMH batteries
- palladium hydride: catalyst in organic reactions; electrodes in cold fusion experiments
- lithium aluminum hydride: a powerful reducing agent used in organic chemistry
- sodium borohydride: selective specialty reducing agent, hydrogen storage in fuel cells
- sodium hydride: a powerful base used in organic chemistry
- diborane: reducing agent, rocket fuel, semiconductor dopant, catalyst, used in organic synthesis; also borane, pentaborane and decaborane
- arsine: used for doping semiconductors
- stibine: used in semiconductor industry
- phosphine: used for fumigation
- silane: many industrial uses, e.g. manufacture of composite materials and water repellents
- ammonia: coolant, fertilizer, many other industrial uses
See also
Notes
ReferencesISBN links support NWE through referral fees
- Brown Jr., Theodore L., H. Eugene LeMay, Bruce Edward Bursten, and Julia R. Burdge. 2002. Chemistry: The Central Science. 9th ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0130669970.
- Chang, Raymond. 2006. Chemistry, 9th ed. New York: McGraw-Hill Science/Engineering/Math. ISBN 0073221031.
- Cotton, F. Albert, and Geoffrey Wilkinson. 1980. Advanced Inorganic Chemistry, 4th ed. New York: Wiley. ISBN 0471027758.
- McMurry, J., and R.C. Fay. 2004. Chemistry, 4th ed. Upper Saddle River, NJ: Prentice Hall. ISBN 0131402080.
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