The phase relation and the dehydration behavior of barium nitrite hydrates have been examined by DTA under various external pressures, and by TG-DTA in air. The equilibrium water vapor pressures of the mono-, hemi-, and 1/3-hydrates have been measured. The temperatures of III-II and II-I phase transitions and melting point of the anhydrate are 469, 497 and 542 K, respectively. The hydration in the atmosphere proceeds as follows:
Monohydrate - 372 K -> Hemihydrate - 425 K -> 1/3-hydrate - 457 K -> Anhydrate.
(Thermochim. Acta, 127, 201-208 (1988))
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