Definition of trigonal in English:

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Pronunciation: /ˈtriɡənl/


1Triangular: square or trigonal double-sided inserts
More example sentences
  • Its morphology is either hexagonal or trigonal.
  • The trigonal planar arrangement of the groups around the carbonyl carbon atom enables the carbon atom to be relatively open to attack from above, or below.
  • Rhodochrosite crystallizes in the trigonal class of the hexagonal system and occurs in a number of diverse forms.
1.1chiefly Biology Triangular in cross section: large trigonal shells
More example sentences
  • The triangular habit suggested trigonal symmetry and a possible identification as hilairite or a contact-twinned form of gaidonnayite.
  • The auricles in early ontogeny are relatively large and distinctly trigonal, with their free margins meeting the hinge line at acute angles.
  • At the same time, however, it has been reported that the zeta line is constructed to position a thick filament at the trigonal point of the three thin filaments in the opposite sarcomere.
1.2Of or denoting a crystal system or three-dimensional geometric arrangement having three equal axes separated by equal angles that are not right angles.
Example sentences
  • These are, in order of decreasing symmetry, the cubic, hexagonal, tetragonal, trigonal, orthorhombic, monoclinic, and triclinic systems.
  • Hexagonal crystals (such as aquamarine and emerald) are useful in defining our goals and successes, whilst trigonal crystal systems (ie tourmaline and amethyst) help us to focus on simplicity.
  • Simple binuclear and trinuclear complexes form linear and trigonal arrangements but a tetranuclear complex can occur as a tetrahedron or a cubane structure.



Example sentences
  • The alkene carbon-carbon double bond is made from two sp trigonally hybridized carbons.
  • This implies that the triad axes exist in the centers of the rings, and hence they are distorted trigonally as in the hexagonal SrAl2O4.
  • The structure of the unit is a trigonally planar one in RTP.


Late 16th century: from medieval Latin trigonalis, from Latin trigonum (see trigon).

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