The molecular geometry of hydrogen cyanide (HCN) is linear.
In HCN, there are three atoms: hydrogen (H), carbon (C), and nitrogen (N). The central atom is carbon, which is bonded to both hydrogen and nitrogen. The arrangement of these atoms is governed by the Lewis structure of the molecule, where carbon forms a triple bond with nitrogen and a single bond with hydrogen.
Due to the triple bond between carbon and nitrogen, as well as the single bond to hydrogen, the molecule adopts a straight line shape. The bond angles in HCN are approximately 180 degrees. This linear geometry can be attributed to the fact that there are two regions of electron density around the central carbon atom, leading to a minimal repulsion between the bonds.