Low-temperature heat capacity and high-temperature thermal behavior of sodium lutetium molybdate phosphate Na2Lu(MoO4)(PO4)
| Autor: | Andrey V. Khoroshilov, K. S. Gavrichev, M. A. Ryumin, G. A. Sharpataya, N. N. Smirnova, L. N. Komissarova, V. M. Gurevich, A. V. Tyurin, V. P. Danilov |
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| Rok vydání: | 2007 |
| Předmět: |
Materials Science (miscellaneous)
Sodium Enthalpy Analytical chemistry chemistry.chemical_element Thermodynamics Calorimetry Molybdate Heat capacity Lutetium Inorganic Chemistry chemistry.chemical_compound Differential scanning calorimetry chemistry Physical and Theoretical Chemistry Powder diffraction |
| Zdroj: | Russian Journal of Inorganic Chemistry. 52:727-732 |
| ISSN: | 1531-8613 0036-0236 |
| DOI: | 10.1134/s0036023607050129 |
| Popis: | The low-temperature heat capacity of Na2Lu (MoO4)(PO4) was measured by adiabatic calorimetry in the range of 7.47–345.74 K. The experimental data were used to calculate the thermodynamic functions of Na2Lu (MoO4)(PO4). At 298.15 K, the following values were obtained: Cp0(298.15 K) = 237.7 ± 0.1 J/(K mol), S0(298.15 K) = 278.1 ± 0.8 J/(K mol), H0(298.15 K) − H0 (0 K) = 42330 ± 20 J/mol, and Φ0(298.15 K) = 136.1 ± 0. 3 J/(K mol). A heat capacity anomaly was found in the range of 10-67 K with a maximum at Ttr = 39.18 K. The entropy and enthalpy of transition are ΔS = 12.39 ± 0.75 J/(K mol) and ΔH = 403 ± 16 J/mol. The thermal investigation of sodium lutetium molybdate phosphate in the high-temperature range (623–1223 K) was performed using differential scanning calorimetry. It was found that during melting in the range of 1030–1200 K, Na2Lu(MoO4)(PO4) degrades to simpler compounds; the degradation scenario is verified by X-ray powder diffraction. |
| Databáze: | OpenAIRE |
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