I always wondered about the question why Sugar dissolves like salt, without being ionic.

Now my question is: How does sugar forms a crystal if it is a covalent compound? Are there very strong IMF's? (Intermolecular Forces)

I'd appreciate learning any knowledge about the subject.

  • 1
    $\begingroup$ Probably a better fit for Chemistry $\endgroup$ – user154997 Aug 27 '17 at 5:01

The answer to both of your questions is the same: Hydrogen bonds. Let me take the example of two neighbour molecules of sucrose in a crystal:

enter image description here

One Oxygen atom from the molecule on the left and one Hydrogen atom from the molecule on the right attract each other, leading to what is known as a Hydrogen bond, represented by the dashed line. I have only represented one Hydrogen bond to keep the picture readable but of course each molecule is then Hydrogen bonded to others.

Hydrogen bonds, with water molecule this times, also explain the solubility of Sucrose.

  • $\begingroup$ Thanks a lot. I knew what hydrogen bonding is, I myself am taking a Chemistry course, but I wasn't aware of the behavior of glucose molecules in a crystalline form. $\endgroup$ – Julius Aug 31 '17 at 2:53
  • $\begingroup$ Note that this applies to the crystalline form of pretty much any neutral molecule. Note also that finding the network of Hydrogen bonds in a such a crystal, by that I mean replace each molecule with a dot and draw the H-bond to the other molecules, is a very important activity in molecular crystallography. $\endgroup$ – user154997 Aug 31 '17 at 6:23

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