The molecular geometry of hydrogen cyanide (HCN) is linear.
To determine the molecular geometry, we start by looking at the structure of HCN. The molecule consists of three atoms: hydrogen (H), carbon (C), and nitrogen (N). The carbon atom is at the center, attached to one hydrogen atom and one nitrogen atom.
HCN can be represented as H-C≡N. The carbon atom forms a triple bond with nitrogen and a single bond with hydrogen. This arrangement results in a straight line from hydrogen to nitrogen through carbon, creating a linear molecular shape.
Additionally, HCN has a total of 2 atoms bonded to the central carbon atom and no lone pairs of electrons on the carbon. According to VSEPR (Valence Shell Electron Pair Repulsion) theory, when there are two bonded atoms and no lone pairs, the molecular geometry is classified as linear. Thus, the angle between the atoms is approximately 180 degrees.
In summary, the molecular geometry of HCN is linear due to the arrangement of its bonds, confirming that the structure is straight and the bond angle is 180 degrees.