Is AsH3 polar or nonpolar? - Polarity of AsH3
The question is –
Is AsH3 polar or non-polar?
⇒ AsH3 is a polar molecule.
AsH3 is polar as the dipole moments of slightly polar As-H bonds do not get canceled in the asymmetrical trigonal pyramidal shape of the molecule.
AsH3 consists of three As-H bonds and 1 lone pair of electrons on the central arsenic (As) atom.
Each As-H bond is very weakly polar owing to a minute electronegativity difference of 0.02 units between the bonded As-atom (E.N = 2.18) and H-atom (E.N = 2.20).
Therefore, the central As-atom gains a partial positive (δ+) charge while each terminal H-atom obtains partial negative (δ–) charges in the AsH3 molecule.
The small dipole moment of each As-H bond thus points from Asδ+ to Hδ- in AsH3.
One lone pair of electrons surrounds the central As-atom, which leads to lone pair-bond pair electronic repulsions; hence distortion in the overall molecular shape.
AsH3 thus adopts an asymmetrical trigonal pyramidal molecular shape and geometry. The dipole moment vectors of As-H bonds do not get canceled.
Consequently, the charged electron cloud stays non-uniformly spread over the molecule, and the overall polarity effect is enhanced.
As a result, AsH3 is a polar molecule with a permanent dipole moment of net µ = 1.4 Debye.
⇒ How to know if a compound is polar or nonpolar?
About the author
Vishal Goyal is the founder of Topblogtenz, a comprehensive resource for students seeking guidance and support in their chemistry studies. He holds a degree in B.Tech (Chemical Engineering) and has four years of experience as a chemistry tutor. The team at Topblogtenz includes experts like experienced researchers, professors, and educators, with the goal of making complex subjects like chemistry accessible and understandable for all. A passion for sharing knowledge and a love for chemistry and science drives the team behind the website. Let's connect through LinkedIn: https://www.linkedin.com/in/vishal-goyal-2926a122b/