The spinels are any of a class of minerals of general formulation AB 2X 4 which crystallise in the cubic (isometric) crystal system, with the X anions (typically chalcogens, like oxygen and sulfur) arranged in a cubic close-packed lattice and the cations A and B occupying some or all of the octahedral and tetrahedral sites in the lattice.[1][2] Although the charges of A and B in the prototypical spinel structure are +2 and +3, respectively (A2+ B3+ 2X2− 4), other combinations incorporating divalent, trivalent, or tetravalent cations, including magnesium, zinc, iron, manganese, aluminium, chromium, titanium, and silicon, are also possible. The anion is normally oxygen; when other chalcogenides constitute the anion sublattice the structure is referred to as a thiospinel.
A and B can also be the same metal with different valences, as is the case with magnetite, Fe3O4 (as Fe2+ Fe3+ 2O2− 4), which is the most abundant member of the spinel group.[3] Spinels are grouped in series by the B cation.
The group is named for spinel (MgAl 2O 4), which was once known as "spinel ruby".[4] (Today the term ruby is used only for corundum.)
^Robert J. Naumann: Introduction to the Physics and Chemistry of Materials CRC Press, 2008, ISBN 978-1-4200-6134-5. Retrieved 15 April 2018.
^H-J Meyer: Festkörperchemie in: H-J Meyer (ed.), Riedel Moderne Anorganische Chemie, Walter de Gruyter, 2012, ISBN 978-3-11-024900-2. Retrieved 15 April 2018.
^Ernst, W. G. (1969). Earth Materials (Print ed.). Englewood Cliffs, NJ: Prentice-Hall. p. 58.
of the spinelgroup. Spinels are grouped in series by the B cation. The group is named for spinel (MgAl 2O 4), which was once known as "spinel ruby"....
Spinel (/spɪˈnɛl, ˈspɪnəl/) is the magnesium/aluminium member of the larger spinelgroup of minerals. It has the formula MgAl 2O 4 in the cubic crystal...
Ringwoodite is polymorphous with forsterite, Mg2SiO4, and has a spinel structure. Spinelgroup minerals crystallize in the isometric system with an octahedral...
Gahnite, ZnAl2O4, is a rare mineral belonging to the spinelgroup. It forms octahedral crystals which may be green, blue, yellow, brown or grey. It often...
chemical formula of FeCr2O4. It is an oxide mineral belonging to the spinelgroup. The element magnesium can substitute for iron in variable amounts as...
mineral belonging to the normal spinel subgroup's iron (Fe) series, with the formula Zn2+Fe23+O4. As with another spinel member magnetite, both ferrous...
ions and unit cell length is a = 0.839 nm. As a member of the inverse spinelgroup, magnetite can form solid solutions with similarly structured minerals...
Hercynite is a spinel mineral with the formula FeAl2O4. It occurs in high-grade metamorphosed iron-rich argillaceous (clay-containing) sediments as well...
mogensenite, Ti-magnetite, or titanian magnetite. It is part of the spinelgroup of minerals. The Curie temperature for titanomagnetite has been found...
Galaxite, also known as 'mangan-spinel' is an isometric mineral belonging to the spinelgroup of oxides with the ideal chemical formula Mn2+Al2O4. Galaxite...
is a magnesium iron oxide mineral, a member of the magnetite series of spinels. Magnesioferrite crystallizes as black metallic octahedral crystals. It...
Filipstadite is a very rare mineral of the spinelgroup, with the formula (Mn,Mg)(Sb5+0.5Fe3+0.5)O4. It is isometric, although it was previously thought...
hydrazine, or reacting iron oxides and zinc oxide at high temperature. Spinel (Zn, Fe) Fe2O4 appears as a tan-colored solid that is insoluble in water...
Zincochromite Zincochromite found in Russia General Category Spinelgroup Formula (repeating unit) ZnCr2O4 IMA symbol Zchr Strunz classification 4.BB.05...
A ternary compound of type A2BX4 may be in the class of olivine, the spinelgroup, or phenakite. Examples include K2NiF4, β-K2SO4, and CaFe2O4. One of...
for magnetite (Fe3O4), the corresponding iron oxide. It belongs to the spinelgroup and forms tetragonal crystals. Hausmannite is a brown to black metallic...
Jacobsite is a manganese iron oxide mineral. It is in the spinelgroup and forms a solid solution series with magnetite. The chemical formula is (Mn,Mg)Fe2O4...
temperatures of those minerals. The Curie temperature of magnetite, a spinel-group iron oxide, is about 580 °C, whereas most basalt and gabbro are completely...
Fe2+) Al2O4, putting it into a group of minerals known as the spinelgroup, or the oxide spinels. The oxide spinels have a formula of the model [A][B]2O4;...
pyrope garnet, Cr-diopside, magnesian ilmenite, and spinel. Olivine lamproites were previously called group II kimberlite or orangeite in response to the mistaken...
chromium oxide mineral with formula Fe2+Cr2O4. It is a member of the spinelgroup and a high pressure polymorph of chromite. It was discovered in samples...
Cuprospinel is a mineral. Cuprospinel is an inverse spinel with the chemical formula CuFe2O4, where copper substitutes some of the iron cations in the...
"Tribute to the World") is an unfaceted, 352.54-carat (71 g) polished red spinel set in a necklace. It is named after the ruler Timur, founder of the Timurid...
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