Linear Geometry
A molecular shape in which the bonded atoms lie on a straight line, giving a bond angle of 180°.
Formula / equation
AX₂ or AX₂E₃
Unit
degrees
In depth
Linear geometry arises with two electron domains and no lone pairs, or from an octahedral arrangement with four lone pairs. Symmetric linear molecules are always non-polar because opposing bond dipoles cancel exactly, however polar the individual bonds may be.
Examples in the real world
CO₂, BeCl₂ and HCN; the triiodide ion I₃⁻ is linear despite having three lone pairs on the central iodine.