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.