Sodium hyperoxide

Crystal structure
	__ Na + __ O 2 -
General
Surname	Sodium hyperoxide
other names	Sodium dioxide; Sodium peroxide;
Ratio formula	NaO 2
Brief description	easily decomposable yellow solid
External identifiers / databases
PubChem	61542
ChemSpider	55460
Wikidata	Q414212
properties
Molar mass	54.99 g mol −1
Physical state	firmly
density	2.2 g cm −3
Melting point	552 ° C (decomposition)
safety instructions
GHS hazard labeling ; no classification available
GHS hazard labeling ; no classification available
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Sodium hyperoxide is a chemical compound with the formula NaO ₂ from the group of hyperoxides .

Representation and occurrence

It is formed when sodium peroxide reacts with oxygen at high temperatures and pressures (e.g. when meteorites enter the earth's atmosphere) and occurs in some minerals .

{\ displaystyle \ mathrm {Na_ {2} O_ {2} + O_ {2} \ {\ xrightarrow [{138 \ bar}] {450 \, {} ^ {\ circ} C}} \ 2 \ NaO_ {2 }}}

properties

Sodium hyperoxide decomposes on contact with water ( hydrolysis ) to sodium hydroxide and oxygen and / or hydrogen peroxide :

{\ displaystyle \ mathrm {4 \ NaO_ {2} +2 \ H_ {2} O \ longrightarrow 4 \ NaOH + 3 \ O_ {2}}}

{\ displaystyle \ mathrm {2 \ NaO_ {2} +2 \ H_ {2} O \ longrightarrow 2 \ NaOH + \ H_ {2} O_ {2} + \ O_ {2}}}

It occurs in three crystal structures (trimorphic): below −77 ° C in a marcasite structure (similar to FeS ₂ ), between −77 ° C and −50 ° C in a pyrite structure and above −50 ° C similar to common salt ( NaCl ).

The standard enthalpy of formation of sodium hyperoxide is ΔH _f⁰ = -260 kJ / mol.

Future applications

Sodium hyperoxide is currently the subject of battery research . The development of modern metal-air batteries shows great potential in terms of stability, charging and discharging efficiency.

Web links

uni-Kiel: Alkali Metals (PDF file; 2.46 MB)

Individual evidence

↑ Entry on sodium oxides. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.
↑ Sodium Hyperoxide at webelements.com
^ ^A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1176.
↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
↑ ^a ^b Stephen E. Stephanou et al .: Sodium superoxide . In: JC Bailar, Jr. (Ed.): Inorganic Syntheses . tape 4 . McGraw-Hill, Inc., 1953, pp. 82-85 (English).
↑ P. Hartmann et al .: A rechargeable room-temperature sodium superoxide (NaO ₂ ) battery , Nature Materials 12, 2013, pp. 228-232, doi : 10.1038 / nmat3486 .

[1] Entry on sodium oxides. In: Römpp Online . Georg Thieme Verlag, accessed on September 29, 2014.

[webelements-2] Sodium Hyperoxide at webelements.com

[wiberg1-3] A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1176.

[NV-4] This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.

[IS4-5] Stephen E. Stephanou et al .: Sodium superoxide . In: JC Bailar, Jr. (Ed.): Inorganic Syntheses . tape 4 . McGraw-Hill, Inc., 1953, pp. 82-85 (English).

[6] P. Hartmann et al .: A rechargeable room-temperature sodium superoxide (NaO ₂ ) battery , Nature Materials 12, 2013, pp. 228-232, doi : 10.1038 / nmat3486 .