Cobalt green
Cobalt green is an ambiguous term for either of two families of green inorganic pigments. Both are obtained by doping cobalt(II) oxide into colorless host oxides.
| Names | |
|---|---|
| Other names
cinnabar green, turquoise green, Rinman's green, Rinmann's green, zinc green | |
| Identifiers | |
| Properties | |
| Zn1−xCoxO | |
| Insoluble | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Spinel-based cobalt green
Doping Co(II) into Mg(II) and Zn(II) sites of Mg2TiO4 and Zn2TiO4, respectively gives one family of cobalt greens. These materials adopt the spinel structure.[1]
Rinman's green
Rinman's green, also referred to as Rinmann's green, is obtained by doping cobalt(II) oxide into zinc oxide. Sven Rinman, a Swedish chemist, discovered this compound in 1780. Zinc oxide–derived pigments have been used in many industries and processes. It is rarely used because it is a weak chromophore and relatively expensive compared to chromium(III) oxide.
The structure and color of compositions Zn1−xCoxO depends on the value of x. For x ≤ 0.3, the material adopts the Wurzite structure (of ZnO) and is intensely green. For x ≥ 0.7, the material has the sodium chloride structure (of CoO) and is pink. Intermediate values of x give a mixture of the two phases.[2]
Cobalt green has been tested for use in "spintronic" devices. Cobalt green is attractive in this application because it is magnetic at room temperature.[3]
See also
References
- Völz, Hans G. et al. "Pigments, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry, 2006 Wiley-VCH, Weinheim. doi:10.1002/14356007.a20_243.pub2.
- F. Wagenknecht, and R. Juza "Rinmann's Green" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 1092.
- Djerdj, Igor; Jaglicic, Zvonko; Arcon, Denis; Niederberger, Markus. "Co-Doped ZnO nanoparticles: Minireview". Nanoscale. 2: 1096–1104. doi:10.1039/c0nr00148a.