trigon

1. The usual coordination geometries of CuI center are line, planar trigon or tetrahedron with the coordination number from 2 to 4.
   一价铜的配位数一般为2、3或者4，常见的配位构型包括直线型、平面三角形、四面体构型等。

noun

1. a triangular lyre of ancient Greece and Rome

2. (astrology) one of four groups of the zodiac where each group consists of three signs separated from each other by 120 degrees

   Synonym:    triplicity

3. a three-sided polygon

   Synonym:    triangletrilateral