What is the coordination number of fluorite?
What is the coordination number of fluorite?
In the fluorite structure, the cation site (Ca2+) is surrounded by a cubic array of eight F anions, and the anions (F-) in theirs tetrahedral holes have four nearest neighbors. So the structure is said to have 8:4 coordination.
What type of unit cell is fluorite?
The X ions occupy the eight tetrahedral interstitial sites whereas M ions occupy the regular sites of a face-centered cubic (FCC) structure….Fluorite structure.
| Material | Lattice constant (Å) | Crystal structure |
|---|---|---|
| CaF2 | 5.463 | Fluorite (FCC) |
| ZrO2 | 5.14 | Fluorite (FCC) |
| K2O | 6.449 | Antifluorite (FCC) |
| K2S | 7.406 | Antifluorite (FCC) |
Why is simple cubic coordination number 6?
This structure is called simple cubic packing. Each sphere in this structure touches four identical spheres in the same plane. Each atom in this structure can form bonds to its six nearest neighbors. Each sphere is therefore said to have a coordination number of 6.
Which Lattice has the closest packing?
The most efficient conformation atomic spheres can take within a unit cell is known as the closest packing configuration. Densely packed atomic spheres exist in two modes: hexagonal closest packing (HCP) and cubic closest packing (CCP).
How many Colours of fluorite are there?
The most common colors are purple, blue, green, yellow, or colorless. Less common are pink, red, white, brown, and black. Color zoning or banding is commonly present. The color of the fluorite is determined by factors including impurities, exposure to radiation, and the absence of voids of the color centers.
What are the characteristics of fluorite?
| Fluorite | |
|---|---|
| Unit cell | a = 5.4626 Å; Z = 4 |
| Identification | |
| Color | Colorless, although samples are often deeply colored owing to impurities; Purple, lilac, golden-yellow, green, blue, pink, champagne, brown. |
| Crystal habit | Well-formed coarse sized crystals; also nodular, botryoidal, rarely columnar or fibrous; granular, massive |
What is the difference between fluorite and Antifluorite structure?
The antifluorite structure has ccplfcc anions with cations in all (T+ and T-) tetrahedral sites. The difference between antifluorite and fluorite is that anti- fluorite refers to an anion array with tetrahedral cations, whereas fluorite has the inverse arrangement with a ccp cation array and tetrahedral anions.
Is fluorite a conductor?
Fluorite is the mineral form of calcium fluoride (CaF2) and is an important host of fluorine. We found that the electrical conductivity of fluorite is very high at moderate temperature only. The results provide direct evidence that fluorine could be an important species for electrical conduction.
Which is the most efficient packing arrangement?
Crystal Structure: Closest Packing
- The most efficient conformation atomic spheres can take within a unit cell is known as the closest packing configuration.
- Densely packed atomic spheres exist in two modes: hexagonal closest packing (HCP) and cubic closest packing (CCP).
What is the structure of the compound fluorite?
In solid state chemistry, the fluorite structure refers to a common motif for compounds with the formula MX 2. The X ions occupy the eight tetrahedral interstitial sites whereas M ions occupy the regular sites of an FCC structure. Many compounds, notably the common mineral fluorite (CaF 2 ), adopt this structure.
What is the antifluorite structure of calcium fluoride CAF 2?
The fluorite structure of calcium fluoride CaF 2. The antifluorite structure of magnesium silicide Mg 2 Si. ^ Greenwood, Norman N.; Earnshaw, Alan (1997).
What are the lattice constants for fluorite at 300 K?
Lattice constants for fluorite and antifluorite materials at 300 K Material Lattice constant (Å) Crystal structure BaF 2 6.196 Fluorite (FCC) β- PbF 2 5.94 Fluorite (FCC) PuO 2 5.399 Fluorite (FCC) SrF 2 5.7996 Fluorite (FCC)
Which is CCP of Ca2 + and antifluorite ( Li2O )?
Fluorite (CaF2) and Antifluorite (Li2O) Fluorite: CCP of Ca2+with all T+and T-holes filled with F- Antifluorite: CCP of O2-with all T+and T-holes filled with Li+ Coordination= 8, 4 (fluorite) Cation Coord. →Cubic Anion Coord. →Tetrahedral Connectivity →Edge sharing FCa 4