What is spinel structure in solid state?
What is spinel structure in solid state?
Spinel, MgAl2O4 (download cif), is a rare gemstone that was used to imitate rubies. The structure has face-centered cubic symmetry, and is a little heavy to understand. The general formula is AB2O4. The oxygens form an fcc lattice. The A cations occupy tetrahedral holes, and the B cation occupy octahedral holes.
Which of the following has spinel structure?
1) MgAl2O4 has normal spinel structure since both the divalent and trivalent ions are non transition metal ions. There is no question of CFSE. 2) Mn3O4 is a normal spinel since the Mn2+ ion is a high spin d5 system with zero LFSE. Whereas, Mn3+ ion is a high spin d4 system with considerable LFSE.
How many types of spinel structures are there?
The spinel group is divided into three immiscible series: the spinel (aluminum-spinel) series, in which B is aluminum; the chromite (chromium-spinel) series, in which B is chromium; and the magnetite (iron-spinel) series, in which B is iron.
What is spinel and inverse spinel structure?
The key difference between spinel and inverse spinel structure is that in spinel structure, B ions occupy half the octahedral holes while A ions occupy 1/8th of the tetrahedral holes whereas, in inverse spinel structure, all A cations and half of the B cations occupy octahedral sites and the other half of B cations …
How is spinel structure calculated?
The spinel structure is formulated MM’2X4, where M and M’ are tetrahedrally and octahedrally coordinated cations, respectively, and X is an anion (typically O or F). The structure is named after the mineral MgAl2O4, and oxide spinels have the general formula AB2O4.
What is spinel material?
spinel, mineral composed of magnesium aluminum oxide (MgAl2O4) or any member of a group of rock-forming minerals, all of which are metal oxides with the general composition AB2O4, in which A may be magnesium, iron, zinc, manganese, or nickel; B may be aluminum, chromium, or iron; and O is oxygen.
What are spinels and their descriptive structure category?
The spinel structure Normal spinel structures are usually cubic close-packed oxides with eight tetrahedral and four octahedral sites per formula unit. The tetrahedral spaces are smaller than the octahedral spaces. B ions occupy half the octahedral holes, while A ions occupy one-eighth of the tetrahedral holes.
What is spinel in inorganic chemistry?
Spinel is a name of Mixed Ore of Magnesium(Mg) and Aluminium(Al), its molecular formula is MgAlO4 (MgO.Al2O3). Here Mg is in +2 oxid. state and Al is in +3 oxid.
What is the streak of spinel?
White
| Spinel | |
|---|---|
| Mohs scale hardness | 7.5–8.0 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to opaque |
How is spinel formed?
Spinel is typically found in three geologic situations: 1) as crystals in marbles or dolomites that have been subjected to contact metamorphism; 2) as irregularly shaped grains in basic igneous rocks; and, 3) as water-worn crystals and pebbles in alluvial deposits.
What kind of rock is spinel?
Spinel is found as a metamorphic mineral in metamorphosed limestones and silica-poor mudstones.
