The O-C-N bond angle in OCN (thiocyanate ion) is approximately 180 degrees. This linear arrangement results from the sp hybridization of carbon, which allows for the formation of a straight line between the oxygen and nitrogen atoms.
In OCN, the carbon atom is bonded to both oxygen and nitrogen. Due to the arrangement of electron groups around the carbon atom, the geometry is linear. This means the bond angle formed by the oxygen-carbon-nitrogen atoms is essentially 180 degrees.
Furthermore, the presence of multiple bonds between carbon, nitrogen, and oxygen also influences this angle. The double bond typically has a stronger repulsion effect, but in this ion structure, it assists in maintaining that linear form, confirming that the O-C-N bond angle remains close to 180 degrees.