MOLECULAR POLARITYFIELD NOTE 09 / 175
Is AsH3 polar or nonpolar?
AsH3 is very weakly polar due to its trigonal pyramidal geometry, despite the nearly identical electronegativities of arsenic and hydrogen.
Arsine · trigonal pyramidal
The molecule in space
Drag to turn the molecule. Show angles to read the model geometry.
01 / MODEL RECORDIllustrative geometry. Atom sizes and bond thickness are illustrative.How model data is used ↗
Why AsH3 is polar
Arsine has a trigonal pyramidal shape with a lone pair on arsenic, similar to NH3 and PH3. The electronegativities of As (2.18) and H (2.20) are nearly identical, so polarity comes almost entirely from the asymmetric geometry and lone pair, not from bond dipoles.
What to notice
The As–H electronegativity difference is tiny, yet arsine is not perfectly symmetric. Its net polarity is much weaker than ammonia's.
Common questions about AsH3
- 01
What does the Lewis structure of AsH3 show?
As forms three single As–H bonds and keeps one lone pair. That lone pair gives the molecule its pyramidal shape.
- 02
What is the molecular geometry of AsH3?
AsH3 has a trigonal pyramidal molecular geometry. The 3D model shows representative bond angles of 90.8°. These are angles in the illustrative model, not experimental measurements.
- 03
What is the molar mass of AsH3?
AsH3 has an approximate molar mass of 77.95 g/mol, calculated from its formula using abridged standard atomic weights. Natural isotope variation can change the last digits.