Question

Name the compound with all bond angles that are exactly 109 degree 28.

Answer 1

Tetrahedral molecules

• A perfect tetrahedral geometry is formed when a central atom is attached by 4 surrounding atoms, forming a bond angle of 109 5.
• In perfect tetrahedral geometry there is no lone pairs in the molecule's central atom.
• The atoms bonded to the central atom are located at the four corners of a tetrahedron, with $109.5°$ angles between them.
• Tetrahedral geometry is formed by mixing of one s and 3 p orbitals, forming sp3 hybridization.
• The perfect tetrahedral geometry is exhibited by methane, phosphate ion.

Deviation from perfect tetrahedral geometry.

The factors which cause deviation in perfect tetrahedral geometry are:

• Number of lone pairs: If there are more lone pairs on the central atom , then there will be lone pair-bond pair repulsion and bond angle will reduce.
• Size of central atom and surrounding atoms: If the size of central atoms is larger than the surrounding atoms then the surrounding atoms will lie farther apart from each other providing electrons to have more space to occupy and they face less repulsion from other electrons and gap between bond pairs increases resulting in increasing the bond angle.
• Electronegativity of central atoms of surrounding atoms: If central atom is more electronegative than the surrounding electrons then electrons will be attracted more towards them resulting in decreasing the bond angle.

The Compound with all bond angles that are exactly $109.28°$ is Carbon tetrachloride.

Carbon tetrachloride having bond angle of $109.28°$