|
Europia
Europium(III) oxide (Eu2O3), is a chemical compound of europium and oxygen. It is widely used as a red or blue phosphor in Cathode ray tube, television sets and fluorescent lamps, and as an activator for yttrium-based phosphors. It is also an agent for the manufacture of fluorescent glass. Europium fluorescence is used in the anti-counterfeiting phosphors in Euro banknotes. Europium oxide has two common structures: Monoclinic (Pearson symbol, mS30, space group ''C''2/''m'', No. 12) and cubic (Pearson symbol, cI80, space group ''I''a, No. 206). The cubic structure is similar to that of manganese(III) oxide. It may be formed by ignition of europium metal. It can react with acids to form the corresponding europium(III) salts. Gallery File:Tl2O3structure.jpg, Cubic Eu2O3 File:Gd2O3structure.jpg, Monoclinic Eu2O3 References {{DEFAULTSORT:Europium(Iii) Oxide Europium(III) compounds Glass engineering and science Sesquioxides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monoclinic
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic system. They form a parallelogram prism. Hence two pairs of vectors are perpendicular (meet at right angles), while the third pair makes an angle other than 90°. Bravais lattices Two monoclinic Bravais lattices exist: the primitive monoclinic and the base-centered monoclinic. For the base-centered monoclinic lattice, the primitive cell has the shape of an oblique rhombic prism;See , row mC, column Primitive, where the cell parameters are given as a1 = a2, α = β it can be constructed because the two-dimensional centered rectangular base layer can also be described with primitive rhombic axes. Note that the length a of the primitive cell below equals \frac \sqrt of the conventional cell above. Crystal classes The table below org ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
