# Dipole moment and polarity of borazine / borazole / inorganic benzene

What is the dipole moment of borazine? I tried googling it but can't find a reliable source. I searched in JD Lee too. It might have it but I could not find.

This NIST publication lists the dipole moment as zero, while drugfuture.com (I've never heard of this site) reports a value of 0.50 as measured in benzene at $\pu{25^oC}$.

The simplest, but not complete, way to tell if the dipole is zero or not is look for a centre of inversion, which borazine would have if it were flat like benzene.

To be absolutely certain the molecule's point group has to be found. To have a dipole the molecule must belong to $C_1, C_{nv}, (n>1)$ and $C_s$ point groups.

As borazine is not planar (according to wikipedia page) and seems to belong to $C_{3v}$ so it should have a dipole. However, looking at the structure the dipole has to be small due to the way the atoms are arranges around the 3 fold axis and the small displacement of the plane containing the B to that of the N atoms. If you can find B-N, N-H, B-H bond dipole values you could calculate the dipole, at least get an approximate value.

• If I remember correct, borazine is planar $D_\mathrm{3h}$? Apr 16, 2017 at 8:32
• @orthocresol yes $D_{3h}$if planar and so no dipole. Apr 16, 2017 at 8:49

Warning: This is just an effort not complete answer. I also request higher members to give answer / put bounty as this question is not having complete answers.

Borazine is planar. But the borazine ring does not form a perfect hexagon. The bond angle is $$117.1°$$ at the boron atoms and $$122.9°$$ at the nitrogen atoms, giving the molecule distinct symmetry.

Dipole moments are forming exact $$120°$$ with each other resulting in net non zero dipole moment and polar molecule.With support of comments I calculated

Borazine, also known as borazole, is a polar inorganic compound. 3D model : https://chemapps.stolaf.edu/jmol/jmol.php?model=%5BBH-%5D1-%5BNH%2B%5D%3D%5BBH-%5D-%5BNH%2B%5D%3D%5BBH-%5D-%5BNH%2B%5D%3D1

All details are from Wikipedia.

• According to your structure Borazine has point group D3h. Hence it has no dipole moment. See chem.libretexts.org/Bookshelves/… Jun 9, 2021 at 7:32
• Also it would be good to reference where you got the above structure from (and picture if you didn't draw it yourself), I'm guessing en.wikipedia.org/wiki/Borazine Jun 9, 2021 at 7:34
• The issue with Borazine is whether it is flat. If it is, it can't have a net dipole. If it isn't flat (and you can't tell that from the picture above) and the borons are on a different plane to the nitrogens (ie the molecule is puckered) then it inevitably has a dipole but it will be perpendicular to the ring. Jun 9, 2021 at 9:32
• @matt_black I agree with you but source tell what i mentioned.
– Jay
Jun 9, 2021 at 9:55
• @Jay Your answer clearly doesn't agree. The problem is your assumption that the issue is whether the bonds in borazine need to be exactly 120°. Even if they are not, the molecule would not have a net dipole since it still has enough symmetry for the net bon dipoles to cancel. Only if it is non-planar is this not true. Jun 9, 2021 at 9:57