The Lewis structure for C2H2 (acetylene) consists of two carbon atoms triple-bonded to each other, with each carbon atom also bonded to a hydrogen atom. The structure can be represented as H-C≡C-H.
Electron Geometry: The electron geometry around each carbon atom in C2H2 is linear. This is because each carbon atom has two regions of electron density (the triple bond and the single bond to hydrogen), which arrange themselves as far apart as possible, resulting in a 180-degree bond angle.
Molecular Geometry: The molecular geometry of C2H2 is also linear. The triple bond between the two carbon atoms and the single bonds to the hydrogen atoms all lie in a straight line.
Polarity: C2H2 is a nonpolar molecule. Although the carbon-hydrogen bonds are slightly polar, the linear geometry of the molecule means that the bond dipoles cancel each other out, resulting in no overall dipole moment.