How Does the Presence of Impurities Affect the Melting Point of Substances?

[Monroe]

I have tried a quick scan of the web for general information relating to the depression of melting points and found very little available, so i started this thread. The general idea is a depression curve which will help you identify by how much a sample contains impurities. I was looking for data on the depression of melting point of aspirin, which should have a melting point of 135. I would hazard a guess that the depression of freezing point is inversly the same thing. Any info would be appreciated.

 

[chemisttree]

The melting point depression is dependent on the chemical nature of the two or more compounds in the mixture. The mixture that gives you the maximum melting point depression is called the "eutectic" mixture... another search term for you.

There is some good data out there for some eutectic mixtures.