Three Electron Groups Trigonal Planar Geometry

Three Electron Groups Trigonal Planar Geometry 

The Lewis structure of BF3 (another molecule with an incomplete octet) has three electron groups around the central atom  

These three electron groups can maximize their separation by assuming 120° bond angles in a plane—a trigonal planar geometry. Experimental observations of the structure of BF3 again confirm the predictions of VSEPR theory. 

Another molecule with three electron groups, formaldehyde, has one double bond and two single bonds around the central atom  

In determining electron geometry, why do we consider only the electron groups on the central atom In other words, why don t we consider electfon groups on terminal atoms  

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Three Electron Groups Trigonal Planar Geometry... 

When there are three electron groups around the central atom, it is sp hybridized. AB molecules and ions with no lone pairs on the central atom have trigonal planar electronic geometry, trigonal planar molecular geometry and sp hybridization on the central atom. 

Trigonal planar (also plane triangpilar) A term used to describe the electronic geometry around a central atom that has three electron groups. Also used to describe the molecular geometry of a molecule or polyatomic ion that has one atom in the center bonded to three atoms at the eomers of an equilateral triangle (ABj). 

This molecule has three electron groups aroimd the central atom. These three electron groups get as far away from each other as possible, resulting in a bond angle of 120° and a trigonal planar geometry. 

When carbon forms a double bond and two single bonds, there are three electron groups around each carbon atom, and VSEPR theory predicts a trigonal planar geometry. 

The electron geometry that minimizes the repulsions between three electron groups is trigonal planar. 

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