Enthalpic Analysis of Potassium Heptafluorotantalate

Nerád, I., Mikšíková, E. and Daněk, V. Enthalpic Analysis of Potassium Heptafluorotantalate Chemical Papers, Vol.57, No. 2, 2003, 73-77

Document type: Článok z časopisu / Journal Article
Collection: Chemical papers  
 
Attached Files
Name Description MIMEType Size Downloads
n572a73.pdf 572a73.pdf application/pdf 203.61KB 0

Author(s) Nerád, I.
Mikšíková, E.
Daněk, V.
Title Enthalpic Analysis of Potassium Heptafluorotantalate
Journal name Chemical Papers
Publication date 2003
Year available 2003
Volume number 57
Issue number 2
ISSN 0366-6352
Start page 73
End page 77
Place of publication Poland
Publisher Versita
Collection year 2003
Language english
Subject 250000 Chemical Sciences
250200 Inorganic Chemistry
Abstract/Summary The relative enthalpies of two crystalline samples K2TaF7 A, K2TaF7 B and of K2TaF7 melt have been measured by the use of the drop calorimetry in the temperature intervals 600—752◦C, 615—750◦C, and 758—880◦C, respectively. The heat capacities have been determined differentiating the temperature dependences of the relative enthalpies: Cp(K2TaF7 cr, A) = (314 ± 6) J mol−1 K−1, Cp(K2TaF7 cr, B) = (356 ± 7) J mol−1 K−1, and Cp(K2TaF7 melt) = (315 ± 9) J mol−1 K−1. Considerable prefreezing was observed in the temperature dependence of the relative enthalpy of the melt. The onset of the prefreezing effect at cooling of the melt was estimated to be at about 820◦C. The depression of the freezing temperature reached down to the temperature of crystallization of 755◦C. The calorimetric experiments have shown the temperature of fusion to be 752◦C < tfus < 758◦C. The enthalpies of fusion at the temperature of 755◦C, ΔfusH(K2TaF7 A, 755◦C) = (37.2 ± 0.7) kJ mol−1 and ΔfusH(K2TaF7 B, 755◦C) = (34.6 ± 1.0) kJ mol−1, inclusive enthalpy of prefreezing, have been determined from experimental data.
 
 
User Comments
 
Access Statistics: 0 Abstract Views, 0 File Downloads Detailed Statistics
Created: Thu, 07 Jan 2010, 11:40:43 CET by Jana Taptičová . Detailed History