Trigonal planar molecular geometry

{{Short description|Molecular geometry of symmetry D_3h}} {{Infobox molecular geometry | Image_File=Trigonal-3D-balls.png| Symmetry_group= D_3h | Atom_direction=3 | Bond_angle=120° | mu=0 | Examples=SO₃ }} [[Image:Boron-trifluoride-3D-vdW.png|thumb|left|200px|Structure of boron trifluoride, an example of a molecule with trigonal planar geometry.]] In chemistry, '''trigonal planar''' is a molecular geometry model with one atom at the center and three atoms at the corners of an equilateral triangle, called peripheral atoms, all in one plane.<ref name=":0">{{Cite book |last=March |first=Jerry |title=Advanced organic chemistry : reactions, mechanisms, and structure |date=1985 |publisher=Wiley |isbn=0-471-88841-9 |edition=3rd |location=New York |oclc=10998226}}</ref> In an ideal trigonal planar species, all three ligands are identical and all bond angles are 120°. Such species belong to the point group D_3h. Molecules where the three ligands are not identical, such as H₂CO, deviate from this idealized geometry. Examples of molecules with trigonal planar geometry include boron trifluoride (BF₃), formaldehyde (H₂CO), phosgene (COCl₂), and sulfur trioxide (SO₃). Some ions with trigonal planar geometry include nitrate ({{chem|NO|3|−}}), carbonate ({{chem|CO|3|2−}}), and guanidinium ({{chem|C(NH|2|)|3|+}}). In organic chemistry, planar, three-connected carbon centers that are trigonal planar are often described as having sp² hybridization.<ref>{{cite book|last1=Holleman|first1=A. F.|last2=Wiberg|first2=E.|title=Inorganic Chemistry|publisher=Academic Press|location=San Diego|date=2001|isbn=0-12-352651-5}}</ref><ref>{{cite book|first1=G. L.|last1=Miessler|first2=D. A.|last2=Tarr|title=Inorganic Chemistry|year=2004|edition=3rd|publisher=Pearson/Prentice Hall|isbn=0-13-035471-6|url-access=registration|url=https://archive.org/details/inorganicchemist03edmies}}</ref>

Nitrogen inversion is the distortion of pyramidal amines through a transition state that is trigonal planar.

'''Pyramidalization''' is a distortion of this molecular shape towards a tetrahedral molecular geometry. One way to observe this distortion is in pyramidal alkenes.<ref name=":0" />

==See also== *AXE method *Molecular geometry *VSEPR theory

==References== <references/>

==External links== *[http://www.3dchem.com/ 3D Chem Chemistry, Structures, and 3D Molecules] *[http://arquivo.pt/wayback/20160523113736/http://www.iumsc.indiana.edu/ Indiana University Molecular Structure Center] * [http://www.staff.ncl.ac.uk/j.p.goss/symmetry/Molecules_l3d.html Interactive molecular examples for point groups] *[https://web.archive.org/web/20080120023822/http://chemlab.truman.edu/CHEM121Labs/MolecularModeling1.htm Molecular Modeling] *[http://intro.chem.okstate.edu/1314F97/Chapter9/3BP.html Animated Trigonal Planar Visual]

{{MolecularGeometry}}

Category:Molecular geometry