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Inverse spinel structures have a different cation distribution in that all of the A cations and half of the B cations occupy octahedral sites, while the other half of the B cations occupy tetrahedral sites. An example of an inverse spinel is Fe 3 O 4, if the Fe 2+ (A 2+) ions are d 6 high-spin and the Fe 3+ (B 3+) ions are d 5 high-spin.
Polyhedral representation of spinel MgAl 2 O 4. Spinel (/ s p ɪ ˈ n ɛ l, ˈ s p ɪ n əl / [7]) is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula MgAl 2 O 4 in the cubic crystal system. Its name comes from the Latin word spinella, a diminutive form of spine, in reference to its pointed crystals. [5]
Cuprospinel is a mineral.Cuprospinel is an inverse spinel with the chemical formula CuFe 2 O 4, where copper substitutes some of the iron cations in the structure. [4] [5] Its structure is similar to that of magnetite, Fe 3 O 4, yet with slightly different chemical and physical properties due to the presence of copper.
The structure is inverse spinel, with O 2-ions forming a face-centered cubic lattice and iron cations occupying interstitial sites. Half of the Fe 3+ cations occupy tetrahedral sites while the other half, along with Fe 2+ cations, occupy octahedral sites. The unit cell consists of thirty-two O 2-ions and unit cell length is a = 0.839 nm. [15] [16]
An exception exists for ɣ-Fe 2 O 3 which has a spinel crystalline form and is widely used a magnetic recording substrate. [ 16 ] [ 17 ] However the structure is not an ordinary spinel structure , but rather the inverse spinel structure: One eighth of the tetrahedral holes are occupied by B cations, one fourth of the octahedral sites are ...
Mn 3 O 4 has the spinel structure, where the oxide ions are cubic close packed and the Mn II occupy tetrahedral sites and the Mn III octahedral sites. [3] The structure is distorted due to the Jahn–Teller effect. [3]
It belongs to the spinel group of minerals, as does magnetite, Fe 3 O 4. Ulvöspinel forms as solid solutions with magnetite at high temperatures and reducing conditions, and grains crystallized from some basalt - gabbro magmas are rich in the ulvöspinel component.
Co 3 O 4 adopts the normal spinel structure, with Co 2+ ions in tetrahedral interstices and Co 3+ ions in the octahedral interstices of the cubic close-packed lattice of oxide anions. [ 4 ] tetrahedral coordination geometry of Co(II)