crystal system

n (Chemistry) crystallog any of six, or sometimes seven, classifications of crystals depending on their symmetry. The classes are cubic, tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic. Sometimes an additional system, trigonal, is distinguished, although this is usually included in the hexagonal system. See also crystal class

Crystal System

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 = b ≠ c; α = β = γ = 90°), hexagonal (a = b ≠ c; α = β = 90°; γ = 120°), trigonal (a = b = c; α = β = γ ≠ 90°), orthorhombic (a ≠ b ≠ c; α = β = γ = 90°), mono-clinic (a ≠ b ≠ c; α = β = γ = 90°; β ≠ 90°), and triclinic (a ≠ b ≠ c; α ≠ β ≠ γ ≠ 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.

单词	crystal system
释义	crystal system crystal system n (Chemistry) crystallog any of six, or sometimes seven, classifications of crystals depending on their symmetry. The classes are cubic, tetragonal, hexagonal, orthorhombic, monoclinic, and triclinic. Sometimes an additional system, trigonal, is distinguished, although this is usually included in the hexagonal system. See also crystal class Crystal System 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 = b ≠ c; α = β = γ = 90°), hexagonal (a = b ≠ c; α = β = 90°; γ = 120°), trigonal (a = b = c; α = β = γ ≠ 90°), orthorhombic (a ≠ b ≠ c; α = β = γ = 90°), mono-clinic (a ≠ b ≠ c; α = β = γ = 90°; β ≠ 90°), and triclinic (a ≠ b ≠ c; α ≠ β ≠ γ ≠ 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. MedicalSeesystem
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