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Updated: May 30, 2026

A Microfluidic Approach for the Study of Ice and Clathrate Hydrate Crystallization
Published on: August 18, 2022
Single freezing and triple melting of micrometre-scaled (NH4)2SO4/H2O droplets
Anatoli Bogdan1, Mario J Molina, Heikki Tenhu
1Institute of Physical Chemistry, University of Innsbruck, Innsbruck, Austria. anatoli.bogdan@uibk.ac.at
Abstract:
Atmospheric aerosol droplets containing NH(4)(+) and SO(4)(2-) ions are precursors of cirrus ice clouds. However, the low-temperature phase transformation of such droplets is not understood yet. Here we show for the first time that micrometre-scaled (NH(4))(2)SO(4)/H(2)O droplets produce one freezing event but three melting events which are the melting of (i) pure ice, (ii) eutectic ice/(NH(4))(2)SO(4), and (iii) eutectic ice/(NH(4))(3)H(SO(4))(2). We also find that the melting of ice/(NH(4))(3)H(SO(4))(2) consists of two eutectic melting events, presumably ice/letovicite-II and ice/letovicite-III.
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