Cobalt(III) oxide

Last updated
Cobalt(III) oxide [1]
Cobalt(III) oxide.JPG
Names
IUPAC name
cobalt(III) oxide, dicobalt trioxide
Other names
cobaltic oxide, cobalt sesquioxide
Identifiers
3D model (JSmol)
ECHA InfoCard 100.013.779 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 215-156-7
PubChem CID
RTECS number
  • GG2900000
  • InChI=1S/2Co.3O
    Key: UPWOEMHINGJHOB-UHFFFAOYSA-N
  • O=[Co]O[Co]=O
Properties
Co2O3
Molar mass 165.8646 g/mol
Appearancered powder
Density 5.18 g/cm3 [2]
Melting point 895 [3]  °C (1,643 °F; 1,168 K)
negligible
+4560.0·10−6 cm3/mol
Structure
Corundum, hR30
R3c, No. 167
Thermochemistry
-577 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
toxic
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-silhouette.svg
Warning
H302, H317, H351, H410
P280
NFPA 704 (fire diamond)
3
0
0
OX
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Cobalt(III) oxide is the inorganic compound with the formula of Co2O3. Although only two oxides of cobalt are well characterized, CoO and Co3O4, [4] procedures claiming to give Co2O3 have been described. Thus treatment of Co(II) salts such as cobalt(II) sulfate with an aqueous solution of sodium hypochlorite (also known as bleach) gives a black solid: [5] [6]

2CoSO4 + 4NaOH + NaOCl → Co2O3 + 2Na2SO4 + NaCl

Some formulations of the catalyst hopcalite contain "Co2O3".

Some studies have been unable to synthesize the compound, and report that it is theoretically unstable. [7]

It is soluble in cold diluted sulfuric acid and produces Co2[SO4]3, which is blue in aqueous solution.

Co2O3 + 3H2SO4 → Co2[SO4]3 + 3H2O

Cobalt(III) ion is a strong oxidizer in acidic solution, its standard electrode potential is +1.84V in this situation. [8]

See also

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2
. The compound forms several hydrates CoCl
2
·nH
2
O
, for n = 1, 2, 6, and 9. Claims of the formation of tri- and tetrahydrates have not been confirmed. The anhydrous form is a blue crystalline solid; the dihydrate is purple and the hexahydrate is pink. Commercial samples are usually the hexahydrate, which is one of the most commonly used cobalt compounds in the lab.

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<span class="mw-page-title-main">Bismuth(III) iodide</span> Chemical compound

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Cobalt(II) hydroxide or cobaltous hydroxide is the inorganic compound with the formula Co(OH)
2
, consisting of divalent cobalt cations Co2+
and hydroxide anions HO
. The pure compound, often called the "beta form" is a pink solid insoluble in water.

Cobalt compounds are chemical compounds formed by cobalt with other elements. In the compound, the most stable oxidation state of cobalt is the +2 oxidation state, and in the presence of specific ligands, there are also stable compounds with +3 valence. In addition, there are cobalt compounds in high oxidation states +4, +5 and low oxidation states -1, 0, +1.

References

  1. Sigma-Aldrich product page
  2. Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN   0-8493-0487-3.
  3. "1308-04-9 CAS MSDS (COBALT(III) OXIDE BLACK) Melting Point Boiling Point Density CAS Chemical Properties".
  4. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  5. Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. p. 1675.
  6. Hüttner, Erwin (1901-05-02). "Beiträge zur Kenntnis der Oxyde des Kobalts". Zeitschrift für anorganische Chemie (in German). Wiley. 27 (1): 81–124. doi:10.1002/zaac.19010270113. ISSN   0863-1778.
  7. Shanbhag, Pavitra N.; Biswas, Raju K.; Pati, Swapan K.; Sundaresan, Athinarayanan; Rao, Chinthamani Nagesa Ramachandra (2020-11-02). "Elusive Co2O3: A Combined Experimental and Theoretical Study". ACS Omega. American Chemical Society (ACS). 5 (45): 29009–29016. doi:10.1021/acsomega.0c03397. ISSN   2470-1343. PMC   7675568 . PMID   33225132.
  8. Guoqing, Wu (2003). 无机化学 (Inorganic Chemistry) (4th ed.). People's Republic of China: 高等教育出版社 (Higher Education Press). p. 781. ISBN   9787040115833.