Microscope Observations of Crystals Appearing in the Process of Cooling Aqueous Solutions of Alcohols
スポンサーリンク
概要
- 論文の詳細を見る
The crystals growing from aqueous solutions of alcohols (methanol, ethanol, iso-propanol, n-propanol, ethylene glycol, propylene glycol, and glycerol) were photographed with ordinary and movie (16 mm) cameras through a microscope. The sample was cooled the use of liquid oxygen (or nitrogen). The temperatures measured thermocouples were recorded automatically. Crystal forms were classified into two main groups, i. e., hexagonal crystal and cubic crystal. To the former belong hexagonal fernlike crystals, "soft" hexagonal plates, and "soft" spherical crystals, and to the latter cubic crystals that appear only in ethanol, n-propanol, and iso-propanol solutions. Among the cubic crystals, only the one appearing in iso-propanol solution was found to show double refraction at temperatures below -51°〜-52℃. Phase transition does occur in the crystal. The crystal systems below and above the transition temperature are most probably tetragonal and cubic, respectively, as inferred from the analogy of similar phase transition in metals and other substances. The results of centrifugal precipitation and the similarity in crystal form to snow indicate that the constituent of hexagonal crystals may well be assumed as ice. What the cubic crystal consists of remains as yet unknown, though the fact that various concentrations and cooling speeds always lead to phase transition at the same temperature gives a positive proof of the definite proportion of constituents (alcohol and water). The growing speed of cubic crystals is much faster than that of hexagonal crystals, which also seems to suggest that the constituents of cubic crystal are the associated molecules of water and alcohol.
- 社団法人日本物理学会の論文
- 1961-10-05
著者
-
Yamaji Kenji
Institute Of Low Temperature Science Hokkaido University
-
Yamaji K.
Institute of Low, Temperature Science, Hokkaido University