一、熔点与物性結晶性固体在一个大气压下由固态轉变为液态时的温度叫作熔点。在这个温度固态与液态共存保持不变。純净的有机化合物由固态轉为液态时的熔距很小(約0.5°),因此熔点被用为鑑別有机化合物的重要物理常数。純净有机化合物中如杂有其他成分时,根据那烏特(Raoult)定律,使該化合物在液态时的蒸气压減低而至降低熔点,因此不同成分組成的混合物恒較各組成成分的單独熔点为低。低(共)熔点混合物即屬此类情况。借助这一原 First, the melting point and physical properties of a crystalline solid at a pressure from the solid state into a liquid when the temperature is called the melting point. At this temperature, the coexistence of solid and liquid remains unchanged. The melting distance of a pure organic compound from a solid state to a liquid state is small (about 0.5°), so the melting point is used as an important physical constant for identifying organic compounds. In the case of other compounds in pure organic compounds, according to Raoult’s law, the vapor pressure of the compound in the liquid state is reduced to lower the melting point. Therefore, the composition of different components is always more independent than that of each component. The melting point is low. This is the case for low (co) melting point mixtures. With this original