Hybridisation of H₃O⁺
O is sp³ hybridised (hybridization by the VSEPR count): 3 sigma bonds and 1 lone pair give a trigonal pyramidal shape, bond angle less than 109.5°.
Why this shape
- O has 6 valence electrons. In the Lewis structure it makes three single bonds to H and keeps one lone pair, which leaves it a formal charge of +1.
- Steric number = three sigma bonds + one lone pair = 4, so O is sp³ hybridised.
- Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape.
- Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is less than 109.5°, less than the ideal 109.5°.
- H₃O⁺ is an ion with an overall charge of +1, so it is not described as polar or non-polar.
Lewis structure
8 valence electronsFormal charges: O +1
Why this hybridisation and shape
- O has 6 valence electrons. In the Lewis structure it makes three single bonds to H and keeps one lone pair, which leaves it a formal charge of +1.
- Steric number = three sigma bonds + one lone pair = 4, so O is sp³ hybridised.
- Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape.
- Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is less than 109.5°, less than the ideal 109.5°.
- H₃O⁺ is an ion with an overall charge of +1, so it is not described as polar or non-polar.
Class 11, Chapter 4 Chemical Bonding and Molecular Structure.
Hybridisation of H3O+: quick answers
What is the hybridisation of H3O+?
O has 6 valence electrons. In the Lewis structure it makes three single bonds to H and keeps one lone pair, which leaves it a formal charge of +1. Steric number = three sigma bonds + one lone pair = 4, so O is sp³ hybridised.
What is the shape of H3O+ and its bond angle?
Trigonal pyramidal, with a bond angle of less than 109.5 degrees. Four electron pairs point to the corners of a tetrahedron (tetrahedral electron geometry). With one lone pair in place of atoms, the atoms make a trigonal pyramidal shape. Repulsion falls in the order lone pair to lone pair > lone pair to bond pair > bond pair to bond pair. The lone pair pushes the bond pairs closer, so the angle is less than 109.5°, less than the ideal 109.5°.
How many lone pairs are on the central atom of H3O+?
1 lone pair. O has 6 valence electrons. In the Lewis structure it makes three single bonds to H and keeps one lone pair, which leaves it a formal charge of +1.