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Heat capacities and entropies at 298.15 K of MgTiO3 (geikielite), ZnO (zincite), and ZnCO3 (smithsonite)

Journal of Chemical Thermodynamics

By:
, ,
DOI: 10.1016/0021-9614(89)90058-X

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Abstract

Heat capacities of synthetic MgTiO3 (geikielite), ZnO (zincite), and natural crystals of smithsonite (ZnCO3) were measured between 9 and 366 K using an automatic adiabatically shielded calorimeter. At 298.15 K the standard molar entropies Smo of MgTiO3, ZnO, and ZnCO3 are (74.64 ?? 0.15), (43.16 ?? 0.09), and (81.19 ?? 0.16) J??K-1??mol-1, respectively. Debye temperatures for MgTiO3 and ZnO calculated from our Cp, mo values below 20 K are (900 ?? 20) K and (440 ?? 25) K respectively. Heat capacities for MgTiO3 and ZnO were combined with enthalpy increments from the literature to derive heat-capacity equations for these phases from 260 to about 1800 K. The heat capacities of MgTiO3 between 260 and 1720 K were fitted with an average deviation of 0.3 per cent by the equation: C??p,m/(J??K-1??mol-1) = 222.5-0.05274(T/K)-6.092x105(T/K)-1-1874.6(T/K) -1/2+1.878x10-5(T/K)2 and for ZnO the equation: C??p,m/(J??K-1??mol-1) = 53.999+7.851x10-4(T/K)-5.868x105(T/K)-2 -127.50(T/K)-:1/2+1.9376x10-6(T/K)2 fits the heat capacities in the temperature interval of 250 to 1800 K with an average deviation of 0.7 per cent. ?? 1989.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Heat capacities and entropies at 298.15 K of MgTiO3 (geikielite), ZnO (zincite), and ZnCO3 (smithsonite)
Series title:
Journal of Chemical Thermodynamics
DOI:
10.1016/0021-9614(89)90058-X
Volume
21
Issue:
7
Year Published:
1989
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
743
Last page:
749
Number of Pages:
7