Sodium compounds

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ionic compounds
. It can also form intermetallic compounds and organosodium compounds. Sodium compounds are often soluble in water.

Metallic sodium

Metallic sodium is generally less reactive than

standard reduction potential for the Na+/Na couple being −2.71 volts,[3] though potassium and lithium have even more negative potentials.[4]
The thermal, fluidic, chemical, and nuclear properties of molten sodium metal have caused it to be one of the main coolants of choice for the
fast breeder reactor. Such nuclear reactors are seen as a crucial step for the production of clean energy.[5]

Salts and oxides

See also: Category:Sodium compounds
The structure of sodium chloride, showing octahedral coordination around Na+ and Cl− centres. This framework disintegrates when dissolved in water and reassembles when the water evaporates.

Sodium compounds are of immense commercial importance, being particularly central to industries producing

Lewis acid.[8]

Two equivalent images of the chemical structure of sodium stearate, a typical soap.

Most soaps are sodium salts of fatty acids. Sodium soaps have a higher melting temperature (and seem "harder") than potassium soaps.[7] Sodium containing mixed oxides are promising catalysts[9] and photocatalysts.[10] Photochemically intercalated sodium ion enhances the photoelectrocatalytic activity of WO3.[11]

Like all the alkali metals, sodium reacts exothermically with water. The reaction produces caustic soda (sodium hydroxide) and flammable hydrogen gas. When burned in air, it forms primarily sodium peroxide with some sodium oxide.[12]

Aqueous solutions

Sodium tends to form water-soluble compounds, such as

carboxylates and carbonates. The main aqueous species are the aquo complexes [Na(H2O)n]+, where n = 4–8; with n = 6 indicated from X-ray diffraction data and computer simulations.[13]

Direct precipitation of sodium salts from aqueous solutions is rare because sodium salts typically have a high affinity for water. An exception is

15-crown-5, may be used as a phase-transfer catalyst.[16]

Sodium content of samples is determined by

potentiometry using ion-selective electrodes.[17]

Electrides and sodides

Like the other alkali metals, sodium dissolves in ammonia and some amines to give deeply colored solutions; evaporation of these solutions leaves a shiny film of metallic sodium. The solutions contain the coordination complex (Na(NH3)6)+, with the positive charge counterbalanced by electrons as anions; cryptands permit the isolation of these complexes as crystalline solids. Sodium forms complexes with crown ethers, cryptands and other ligands.[18]

For example,

15-crown-5 has a high affinity for sodium because the cavity size of 15-crown-5 is 1.7–2.2 Å, which is enough to fit the sodium ion (1.9 Å).[19][20] Cryptands, like crown ethers and other ionophores, also have a high affinity for the sodium ion; derivatives of the alkalide Na− are obtainable[21] by the addition of cryptands to solutions of sodium in ammonia via disproportionation.[22]

Organosodium compounds

The structure of the complex of sodium (Na+, shown in yellow) and the antibiotic monensin-A.

Many organosodium compounds have been prepared. Because of the high polarity of the C-Na bonds, they behave like sources of

anions). Some well-known derivatives include sodium cyclopentadienide (NaC5H5) and trityl sodium ((C6H5)3CNa).[23] Sodium naphthalene, Na+[C10H8•]−, a strong reducing agent, forms upon mixing Na and naphthalene in ethereal solutions.[24]

Intermetallic compounds

Sodium forms alloys with many metals, such as potassium,

miscible with sodium, and the 1-2% of it dissolved in the sodium obtained from said mixtures can be precipitated by cooling to 120 °C and filtering.[25]

In a liquid state, sodium is completely miscible with lead. There are several methods to make sodium-lead alloys. One is to melt them together and another is to deposit sodium electrolytically on molten lead cathodes. NaPb3, NaPb, Na9Pb4, Na5Pb2, and Na15Pb4 are some of the known sodium-lead alloys. Sodium also forms alloys with gold (NaAu2) and silver (NaAg2). Group 12 metals (zinc, cadmium and mercury) are known to make alloys with sodium. NaZn13 and NaCd2 are alloys of zinc and cadmium. Sodium and mercury form NaHg, NaHg4, NaHg2, Na3Hg2, and Na3Hg.[26]

See also

References

  1. ISBN 978-1-107-63845-7
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  2. ^ De Leon, N. "Reactivity of Alkali Metals". Indiana University Northwest. Archived from the original on 16 October 2018. Retrieved 7 December 2007.
  3. OCLC 3345182
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  4. OCLC 717012347
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  5. ^ "Fast Neutron Reactors | FBR - World Nuclear Association". World-nuclear.org. Retrieved 2022-10-04.
  6. doi:10.1002/14356007.a24_277
  7. ^
    ISBN 978-3-11-007511-3
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  8. OCLC 34515430
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  9. ISSN 0926-3373
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  10. ISSN 0926-3373. Archived
    from the original on 8 January 2022. Retrieved 8 January 2022.
  11. ISSN 0926-3373
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  12. ^ Greenwood and Earnshaw, p. 84
  13. ISBN 978-0-08-043748-4
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  14. ISBN 978-0-07-016384-3
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  15. ISBN 978-0-85312-027-8
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  16. OCLC 28027599
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  17. PMID 7273405. Archived
    from the original on 5 February 2016. Retrieved 26 November 2011.
  18. ISBN 978-1-4684-3318-0
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  19. ISBN 978-1-4987-2249-0
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  20. ISBN 978-4-431-54186-8
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  21. doi:10.1021/ja00809a060
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  22. OCLC 48056955
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  23. ^ Renfrow, W. B. Jr.; Hauser, C. R. (1943). "Triphenylmethylsodium". Organic Syntheses; Collected Volumes, vol. 2, p. 607.
  24. ^ Greenwood and Earnshaw, p. 111
  25. ISBN 978-1-85166-646-1. Archived
    from the original on 16 December 2021. Retrieved 27 July 2021.
  26. ISBN 978-3-527-61192-8
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