OptiMelt Automated Melting Point System - Stanford Research ...

Chapter 3 Melting Point Determination 59Reference TablesThere is often some uncertainty as to what really is tabulated in melting point tables,especially when a single temperature is listed for a substance.This confusion is based on the fact that while most chemists use the clear point to reportthe melting point temperature of their samples, others prefer the meniscus point. Themeniscus point is often regarded as closer to the true thermodynamic value, since itcorresponds to a coexistence of liquid and solid in the capillary, and is favored by somescientists. However, there is no real thermodynamic justification for that assumption.Luckily, the difference between the two temperatures (clear vs. meniscus point) is, inmost cases, very small and within the accuracy requirements of most determinations.OptiMelt Automated Melting Point System