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Corundum is a crystalline form of aluminium oxide (Al 2 O 3) typically containing traces of iron, titanium, vanadium, and chromium. [3] [4] It is a rock-forming mineral.It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. [7]
In 2008, 3M created the Renewable Energy Division within 3M's Industrial and Transportation Business to focus on Energy Generation and Energy Management. [ 85 ] [ 86 ] In late 2010, the state of Minnesota sued 3M for $5 billion in punitive damages, claiming they released PFCs —classified a toxic chemical by the EPA—into local waterways. [ 87 ]
Under this space group the two A positions are equivalent. If the space group is F 4 3m then the three-fold rotoinversions become simple three-fold rotations (point group C 3v) because the inversion disappears, and the two A positions are no longer equivalent. Every ion is on at least three mirror planes and at least one three-fold rotation axis.
Piezoelectric materials (PMs) can be broadly classified as either crystalline, ceramic, or polymeric. [1] The most commonly produced piezoelectric ceramics are lead zirconate titanate (PZT), barium titanate, and lead titanate. Gallium nitride and zinc oxide can also be regarded as a ceramic due to their relatively wide band gaps.
The following table give predictions for the crystalline structure of elements 85–87, 100–113 and 118; all but radon [2] have not been produced in bulk. Most probably Cn and Fl would be liquids at STP (ignoring radioactive self-heating concerns).
Visualisation of a diamond cubic unit cell: 1. Components of a unit cell, 2. One unit cell, 3. A lattice of 3 × 3 × 3 unit cells. Diamond's cubic structure is in the Fd 3 m space group (space group 227), which follows the face-centered cubic Bravais lattice.
In Hermann–Mauguin notation, space groups are named by a symbol combining the point group identifier with the uppercase letters describing the lattice type.Translations within the lattice in the form of screw axes and glide planes are also noted, giving a complete crystallographic space group.
The space group of the Zincblende structure is called F 4 3m (in Hermann–Mauguin notation), or 216. [50] [51] The Strukturbericht designation is "B3". [52] The Zincblende structure (also written "zinc blende") is named after the mineral zincblende , one form of zinc sulfide (β-ZnS). As in the rock-salt structure, the two atom types form two ...