Crystal System


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crystal system

[¦krist·əl ′sis·təm]
(crystallography)
One of seven categories (cubic, hexagonal, tetragonal, trigonal, orthorhombic, monoclinic, and triclinic) into which a crystal may be classified according to the shape of the unit cell of its Bravais lattice, or according to the dominant symmetry elements of its crystal class.

Crystal System

 

any of the seven groups of crystals obtained when a classification is made according to the symmetry of the unit cell. A system is characterized by the ratios between the a, b, and c axes and by the angles α, β, and γ of the unit cell. The seven systems are cubic (a = b = c; α = β = γ = 90°), tetragonal (a = bc; α = β = γ = 90°), hexagonal (a = bc; α = β = 90°; γ = 120°), trigonal (a = b = c; α = β = γ ≠ 90°), orthorhombic (abc; α = β = γ = 90°), mono-clinic (abc; α = β = γ = 90°; β ≠ 90°), and triclinic (abc; αβγ ≠ 90°). As the broadest classification of crystal symmetry, each crystal system includes several symmetry point groups and Bravais lattices.

REFERENCE

Popov, G. M., and I. I. Shafranovskii. Kristallografiia, 5th ed. Moscow, 1972.
References in periodicals archive ?
We also obtain the structure of the coefficient matrix in the case of thermoelastic waves propagation in anisotropic media, orthorhombic, tetragonal, hexagonal, and cubic crystal systems.
DSC results suggested complex formation in EVP2 (ASCP/UR at a molar ratio of 1/12) and that the tetragonal crystal system of UR changed into a hexagonal crystal system as a result of complex formation.
(c) There are seven possible crystal systems, each of which defines a class of point groups.
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The compound was found to crystallize in the tetragonal crystal system, space group 14/mmm (No.
A new single crystal system which measures the dynamic moduli at several ultrasonic frequencies was designed and constructed as part of this study.
Calcite, the chemical composition of which is CaC[O.sub.3], belongs to the trigonal crystal system and the 167R3C space group; its lattice parameters are as follows: a = 4.99 [Angstrom], b = 4.99 [Angstrom], c = 17.06 [Angstrom], interfacial angle [alpha] = [beta] = 90[degrees], and [gamma] = 120[degrees].
The single crystal XRD study reveals that the grown crystal belongs to orthorhombic crystal system and the obtained lattice parameters are a = 8.05 [Angstrom], b = 8.17 [Angstrom], and c = 9.23 [Angstrom].
Organized alphabetically, each entry summarizes the crystal system, natural production and artificial growth methods, and electrical properties before commenting on transmittance and reflectance spectra, optical constants, the dispersion relation, emissivity, and spectroscopy applications.
We are investigating the long-term gain stability of the APD plus scintillation crystal system and finalizing the design of the photon detector array.
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01-075-1807 Chemical formula [Mg.sub.3][(B[O.sub.3]).sub.2] Molecular weight (g/mol) 190.53 Crystal system Orthorhombic Space group Pnmn a ([Angstrom]) 5.398 b ([Angstrom]) 8.416 C ([Angstrom]) 4.497 [alpha] ([degrees]) 90.00 [beta] ([degrees]) 90.00 [gamma] ([degrees]) 90.00 Z 2.00 Density (g x [cm.sup.-3]) 3.10 Mineral name Suanite pdfno.