What is the lewis structure of TeS2, the steric number, the electron pair geometry, the molecular geometry, and how many double bonds does it have?
The Correct Answer and Explanation is :
The compound tellurium disulfide (TeS2) consists of a central tellurium (Te) atom bonded to two sulfur (S) atoms. Here’s how we can break down the Lewis structure and the related molecular properties:
Lewis Structure:
- Valence Electrons:
- Tellurium (Te) is in Group 16, so it has 6 valence electrons.
- Sulfur (S) is also in Group 16 and has 6 valence electrons per atom.
- Total valence electrons = 6 (Te) + 2 × 6 (S) = 18 valence electrons.
- Bonding:
- Each sulfur atom forms a single bond with tellurium, utilizing 2 electrons per bond (2 × 2 = 4 electrons used).
- The remaining 14 electrons are distributed as lone pairs.
- Electron Pair Distribution:
- Te (with 6 valence electrons) is surrounded by 2 bonding pairs and has 2 lone pairs of electrons.
- S (each with 6 valence electrons) will have 3 lone pairs each after forming a bond with Te.
The resulting Lewis structure will have Te at the center with single bonds to two sulfur atoms. The tellurium atom has two lone pairs, while the sulfur atoms have three lone pairs each.
Steric Number:
The steric number is determined by counting the number of regions of electron density (bonding pairs + lone pairs) around the central atom. In this case, tellurium (Te) has:
- 2 bonding pairs (Te-S bonds) and
- 2 lone pairs.
Thus, the steric number is 4.
Electron Pair Geometry:
With a steric number of 4, the electron pair geometry is tetrahedral.
Molecular Geometry:
Because there are two lone pairs and two bonding pairs, the molecular geometry is bent or V-shaped, similar to the geometry of water (H2O), but with a wider bond angle due to the larger size of tellurium.
Double Bonds:
There are no double bonds in TeS2. The bonding is only single bonds between Te and S, with lone pairs on both the tellurium and sulfur atoms.
Summary:
- Steric number: 4
- Electron pair geometry: Tetrahedral
- Molecular geometry: Bent or V-shaped
- Number of double bonds: 0
This structure is consistent with the behavior of tellurium in compounds where it tends to form single bonds with electronegative elements like sulfur.