CHCl3: a dipole?

Evidence that CHCl3 is non-polar

Some things are in the chemistry misinterpreted. The following facts are often understood to mean that chloroform is non-polar.

• Substances that have a dipole can easily be dissolved in water. Chloroform, i.e. CHCl₃ Difficult to dissolve in water. That speaks against a dipole, but does not exclude it.
• Chloroform is an aprotic solvent, it does not split off protons from the hydrogen. This overlooks the fact that there are also polar aprotic solvents. This property is not indicative of a dipole.
• The idea that a dipole always has something to do with an asymmetry and that the charges do not cancel each other out because they are not arranged symmetrically is not correct. It is about an uneven charge distribution, not a spatially symmetrical structure. The molecule of chloroform has the shape of a tetrahedron, so it is spatially symmetrical. But that says nothing about the charges.
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Why chloroform is a dipole

The atoms of CHCl3 are arranged in a tetrahedron. You should think of it that way.

• The carbon is arranged in the middle of the tetrahedron. The other atoms are located at the 4 corner points, i.e. one hydrogen atom and 3 chlorine atoms.
• In this constellation, the 3 Cl atoms always span a plane that is opposite the H atom.
• The atomic nucleus of chlorine contains 17 protons, which means that there are a total of 51 positive charges in the plane with the chlorine atoms. There is a positive charge on the other side.
• The electrons that move around the C atom, including those shared by hydrogen and chlorine, will therefore be closer to the plane with the chlorine than to the individual charge on the H atom.
• CHCl3 thus forms a dipole. In the vicinity of the "chlorine level" the molecule is negatively charged and in the vicinity of the hydrogen it is positively charged.