A lewis structure for SCl3- along with molecular and electronic geometry.
The Correct Answer and Explanation is :
The Lewis structure for the SCl₃⁻ ion shows sulfur at the center with three chlorine atoms bonded to it. Sulfur has two lone pairs, and there is a negative charge on one chlorine atom, as shown in the diagram above. Let’s break down the molecular and electronic geometry:
- Electron Geometry: The electron geometry refers to the arrangement of electron groups around the central atom. In the case of SCl₃⁻, there are 5 electron groups around the sulfur atom: 3 bonding pairs (from chlorine) and 2 lone pairs. According to the VSEPR theory, this arrangement corresponds to a trigonal bipyramidal electron geometry.
- Molecular Geometry: The molecular geometry considers only the positions of the atoms (ignoring the lone pairs). With 3 bonding pairs and 2 lone pairs, the molecular geometry is T-shaped. The lone pairs occupy the equatorial positions, as they experience less repulsion than bonding pairs in the trigonal bipyramidal arrangement.
- Bond Angles: In a trigonal bipyramidal structure, the ideal bond angles are 90° and 120°. However, due to the presence of lone pairs, the bond angles between the chlorine atoms are slightly distorted from the ideal.
The structure, thus, involves both the electronic arrangement (trigonal bipyramidal) and the molecular arrangement (T-shaped) with a negative charge on one chlorine atom. This configuration ensures the ion is stable and satisfies the octet rule for chlorine, with sulfur able to expand its valence shell.