Cobalt(II,III) oxide
Encyclopedia
Cobalt oxide is inorganic compound
with the formula
Co3O4. It is one of two well characterized cobalt oxides. It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as CoIICoIII2O4 and sometimes as CoO.Co2O3.
close-packed
lattice of oxide
anions.
, CoO, converts to Co3O4 if heated to around 1000 °C in air. Above 900 °C, CoO is stable. These reaction are described by the following equilibrium:
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
Co3O4. It is one of two well characterized cobalt oxides. It is a black antiferromagnetic solid. As a mixed valence compound, its formula is sometimes written as CoIICoIII2O4 and sometimes as CoO.Co2O3.
Structure
Co3O4 adopts the normal spinel structure, with Co2+ ions in tetrahedral interstices and Co3+ ions in the octahedral interstices of the cubicCubic crystal system
In crystallography, the cubic crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals....
close-packed
Close-packing
In geometry, close-packing of equal spheres is a dense arrangement of congruent spheres in an infinite, regular arrangement . Carl Friedrich Gauss proved that the highest average density – that is, the greatest fraction of space occupied by spheres – that can be achieved by a regular lattice...
lattice of oxide
Oxide
An oxide is a chemical compound that contains at least one oxygen atom in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2....
anions.
| |
|
|
| tetrahedral coordination geometry of Co(II) | distorted octahedral coordination geometry of Co(III) | distorted tetrahedral coordination geometry of O |
Synthesis
Cobalt(II) oxideCobalt(II) oxide
Cobalt oxide or cobalt monoxide is an inorganic compound that appears as olive-green to red crystals, or as a greyish or black powder...
, CoO, converts to Co3O4 if heated to around 1000 °C in air. Above 900 °C, CoO is stable. These reaction are described by the following equilibrium:
- Co3O4
3 CoO + 1/2 O2