hexagonal system

      one of the principal categories of structures to which a given crystalline solid can be assigned. Components of crystals in this system are located by reference to four axes—three of equal lengths set at 120° to one another and a fourth, perpendicular to the plane of the other three. If the atoms or atomic groups in the solid are represented by points and the points are connected by line segments, the resulting lattice will define the edges of an orderly stacking of blocks, or unit cells. The hexagonal unit cell is distinguished by the presence of a single line, called an axis of 6-fold symmetry, about which the cell can be rotated by either 60° or 120° without changing its appearance.

      Among the primary crystal systems, the hexagonal system has the fewest substances assigned to it, including arsenic, calcite, dolomite, quartz, apatite, tourmaline, emerald, ruby, cinnabar, and graphite.

      All crystals in the hexagonal system are classed as optically uniaxial, meaning that light travels through the crystal at different speeds in different directions (anisotropy).

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Universalium. 2010.

Look at other dictionaries:

  • Hexagonal system — Hexagonal Hex*ag o*nal, a. [Cf. F. hexagonal.] Having six sides and six angles; six sided. [1913 Webster] {Hexagonal system}. (Crystal.) See under {Crystallization}. [1913 Webster] …   The Collaborative International Dictionary of English

  • hexagonal system — noun : a crystal system characterized by three equal lateral axes intersecting at angles of 60 degrees and a vertical axis of variable length at right angles (as in the hexagonal prism) see crystal system illustration * * * hexagonal system,… …   Useful english dictionary

  • hexagonal system — /hɛkˈsægənəl sɪstəm/ (say hek saguhnuhl sistuhm) noun a system of crystallisation characterised by three equal lateral axes intersecting at angles of 60° and a vertical axis of hexagonal symmetry and of different length at right angles to them …   Australian English dictionary

  • The Hexagonal system — Crystallization Crys tal*li*za tion (kr[i^]s tal*l[i^]*z[=a] sh[u^]n), n. [Cf. F. cristallization.] 1. (Chem. & Min.) The act or process by which a substance in solidifying assumes the form and structure of a crystal, or becomes crystallized; the …   The Collaborative International Dictionary of English

  • Hexagonal — Hex*ag o*nal, a. [Cf. F. hexagonal.] Having six sides and six angles; six sided. [1913 Webster] {Hexagonal system}. (Crystal.) See under {Crystallization}. [1913 Webster] …   The Collaborative International Dictionary of English

  • hexagonal — /hɛkˈsægənəl/ (say hek saguhnuhl) adjective 1. of, relating to, or having the form of a hexagon. 2. having a hexagon as a base or cross section. 3. divided into hexagons, as a surface. 4. Crystallography denoting or relating to the hexagonal… …   Australian English dictionary

  • hexagonal — [hek sag′ə nəl] adj. [ML hexagonalis] 1. of, or having the form of, a hexagon 2. having a six sided base or section: said of a solid figure 3. designating or of a crystal system having three axes of equal length that intersect in the same plane… …   English World dictionary

  • system — [sis′təm] n. [LL systema < Gr systēma (gen. systēmatos) < synistanai, to place together < syn , together + histanai, to set: see STAND] 1. a set or arrangement of things so related or connected as to form a unity or organic whole [a… …   English World dictionary

  • Hexagonal crystal system — In crystallography, the hexagonal is one of the 7 crystal system, it contains 7 point groups . It has the same symmetry as a right prism with a hexagonal base. There is only one hexagonal Bravais lattice, which has six atoms per unit… …   Wikipedia

  • hexagonal crystal system — heksagoninė kristalografinė sistema statusas T sritis fizika atitikmenys: angl. hexagonal crystal system; hexagonal crystallographic system vok. hexagonales Kristallsystem, n rus. гексагональная кристаллическая система, f; гексагональная… …   Fizikos terminų žodynas

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