But, according to https://en.wikipedia.org/wiki/Chemical_polarity ,mfb said:3.0 is a rounded value, they are not exactly the same. The small difference is still more important than the weaker van-der-Waals forces.
This post suggests a notable difference between the electronegativity.
mfb said:There is no sharp line dividing polar and nonpolar. Some bonds are more polar than others.
In the same way, there is no sharp line dividing polar and ionic bonds.
Every bond between atoms of different types is a bit polar. You can set an arbitrary threshold for saying "this is sufficient to call it polar", which can be convenient sometimes, but you do not have to.terryds said:If there is no sharp line dividing polar and non-polar, how to determine if such bond is polar?
By memorizing only??
NCl3 (Nitrogen trichloride) is considered a dipole-dipole molecule because it has a permanent dipole moment due to the unequal sharing of electrons between the nitrogen and chlorine atoms. The nitrogen atom has a higher electronegativity than the chlorine atoms, which results in a partial negative charge on the nitrogen atom and partial positive charges on the chlorine atoms. This creates a dipole moment, making it a dipole-dipole molecule.
The dipole-dipole interaction in NCl3 contributes to the intermolecular force between molecules. The partially positive and negative charges on different molecules attract each other, resulting in a stronger intermolecular force compared to non-polar molecules. This makes it more difficult for NCl3 molecules to separate from each other, resulting in a higher boiling point and stronger intermolecular forces.
Yes, NCl3 can exhibit other types of intermolecular forces, such as London dispersion forces. These forces occur due to temporary fluctuations in electron distribution, creating temporary dipoles and resulting in a weak attraction between molecules. However, the dipole-dipole interaction in NCl3 is stronger than the London dispersion forces, making it the dominant intermolecular force in this molecule.
The molecular geometry of NCl3 is trigonal pyramidal, with the nitrogen atom at the apex and the chlorine atoms at the base. This asymmetrical arrangement results in a permanent dipole moment, with the partially positive and negative charges not canceling each other out. This contributes to the dipole-dipole interaction and the overall polarity of the molecule.
The dipole moment of NCl3 affects its physical properties in several ways. Firstly, it results in a higher boiling point compared to non-polar molecules, as it requires more energy to overcome the stronger intermolecular forces. Secondly, it makes NCl3 soluble in polar solvents, as the polar molecules of the solvent can interact with the partially positive and negative charges of NCl3. Lastly, it can affect the reactivity of NCl3 as the dipole moment can influence the distribution of electrons in chemical reactions.