Why the dipole moment of Co2 is zero and that of H2O is 1.85D?
Chemistry · Middle School · Tue Nov 03 2020
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The dipole moment of a molecule depends on the difference in electronegativity between the atoms and the molecular geometry.
For CO2 (carbon dioxide), it has a linear molecular geometry, and the two oxygen atoms are symmetrically placed on either side of the central carbon atom. The oxygen atoms are highly electronegative, but the dipole moments created by the electronegativity difference cancel each other out due to the molecule's symmetry. As a result, the dipole moment of CO2 is zero.
For H2O (water), it has a bent or V-shaped molecular geometry. The oxygen atom is more electronegative than the hydrogen atoms, leading to a polar covalent bond. The arrangement of atoms in water is not symmetric, and the dipole moments do not cancel out, resulting in a net dipole moment of 1.85D for H2O.