Thermodynamic Properties of (NH[sub 4])[sub 2]KGaF[sub 6] Elpasolite

Flerov, I. N.; Gorev, M. V.; Afanas’ev, M. L.; Ushakova, T. V.
December 2001
Physics of the Solid State;Dec2001, Vol. 43 Issue 12, p2301
Academic Journal
The heat capacity of (NH[sub 4])[sub 2]KGaF[sub 6] elpasolite is measured in the temperature range from 80 to 350 K. A sequence of three phase transitions at T[sub 1] = 288.5 K, T[sub 2] = 250 K, and T[sub 3] = 244.5 K is revealed, and the thermodynamic characteristics of these transitions are determined. The influence of hydrostatic pressure on the phase transition temperature is investigated. The results obtained are discussed within the model of orientational ordering of NH[sup +][sub 4] and GaF[sup 3-][sub 6] ionic groups. © 2001 MAIK “Nauka / Interperiodica”.


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