Cobalt iron stone

Crystal structure
__ Co 2+ / Fe 3+      __ Fe 3+      __ O 2−
General
Surname	Cobalt iron stone
other names	Cobalt ferrite
Ratio formula	CoFe 2 O 4
Brief description	gray solid
External identifiers / databases
CAS number 12052-28-7 EC number 234-992-3 ECHA InfoCard 100,031,799 Wikidata Q1104487
properties
Molar mass	234.63 g mol −1
Physical state	firmly
density	5.3 g cm −3
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 302-317 P: 261-280-301 + 312-302 + 352-321-501
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Cobalt iron stone is a brown, ferrimagnetic solid that crystallizes in the spinel structure . It is a member of the series of solid solutions Co _3-x Fe _x O ₄ which all crystallize in a spinel structure.

Extraction and presentation

Cobalt iron stone can be represented by the reaction of cobalt (II) hydroxide and iron hydroxide .

${\displaystyle \mathrm {Co(OH)_{2}+2Fe(OH)_{3}\longrightarrow CoFe_{2}O_{4}+4H_{2}O} }$

It can also be obtained by reacting cobalt (II) chloride hexahydrate with ammonium iron (III) sulfate or by reacting iron (III) chloride and cobalt (II) chloride with sodium hydroxide .

Physical Properties

Cobalt iron stone exists as an inverse spinel : The oxygen anions form a cubic closest packing of spheres ( ccp ). One eighth of the tetrahedral gaps are occupied by iron (III) cations, a quarter of the octahedral gaps each by other iron (III) cations and cobalt (II) cations. The structure has the space group Fd 3 m (space group no. 227) . Due to its magnetic properties as a non-conductive permanent magnet , the compound was intensively researched in Japan in the 1930s, but was later replaced by the cheaper barium ferrite . A low temperature modification is also known.

use

The compound is ferrimagnetic and, due to its magnetic properties, is used in nanotechnology as a material for high-capacity magnetic storage.

It is also used as a catalyst for the oxidation of alkenes .

Individual evidence

1. ↑ ^{a b c} Datasheet Cobalteisenstein at AlfaAesar, accessed on March 23, 2011 ( PDF )(JavaScript required) .
2. ↑ Nanostructured & Amorphous Materials, Inc. Cobalt Iron Oxides, (CoFe2O4, 98%, 35–55 nm)
3. ^ ^{A b} Terence E. Warner: Synthesis, Properties and Mineralogy of Important Inorganic Materials . John Wiley & Sons, 2012, ISBN 978-0-470-97602-9 , pp. 109 ( limited preview in Google Book search).
4. ↑ D. Fiorani, Gordon Davies, JH Driver, Pierre Steinmetz, Maria Helena Nazaré, Mauro Magini: Synthesis and Properties of Mechanically Alloyed and Nanocrystalline ... 1997, ISBN 0-87849-733-1 , p. 110 ( limited preview in Google Book search).
5. ^ Philipp Kurz, Norbert Stock: Synthetic Inorganic Chemistry Basic Course . Walter de Gruyter, 2013, ISBN 978-3-11-025875-2 , p. 42 ( limited preview in Google Book search).
6. ↑ K. Maaz, Arif Mumtaz, SK Hasanain, Abdullah Ceylan: Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route. In: Journal of Magnetism and Magnetic Materials. 308, 2007, p. 289, doi: 10.1016 / y.jmmm.2006.06.003 .
7. ↑ HP ROOKSBY, BTM WILLIS: Crystal Structure and Magnetic Properties of Cobalt Ferrite at Low Temperatures. In: Nature. 172, 1953, p. 1054, doi: 10.1038 / 1721054c0 .
8. ↑ Fabrication of Superparamagnetic and Ferromagnetic Nanoparticles . ProQuest, 2008, p. 21 ( limited preview in Google Book search).
9. ↑ M. Kooti, ​​M. Afshari: Magnetic cobalt ferrite nanoparticles as an efficient catalyst for oxidation of alkenes. In: Scientia Iranica. 19, 2012, p. 1991, doi: 10.1016 / j.scient.2012.05.005 .