Trigonal Planar Geometry
A flat molecular shape with three bonded atoms arranged around a central atom at 120°.
Formula / equation
AX₃
Unit
degrees
In depth
Three electron domains with no lone pairs give this arrangement, matching sp² hybridisation. The unhybridised p orbital perpendicular to the plane is available for pi bonding or, in electron-deficient species such as BF₃, remains empty and makes the molecule a Lewis acid.
Examples in the real world
BF₃, the carbonate ion CO₃²⁻, and the sp² carbons of ethene and formaldehyde.