Gibbs energy of aluminous minerals

Thompson, Alan Bruce

doi:10.1007/bf00418614

Cited by 21 publications

(3 citation statements)

References 23 publications

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“…The Gibbs energy of the E 1 ' at g = 2.00 has been found to be -68.49 and -61.61 (kJ/mol) for natural and 10 kGy gamma-ray-irradiated amethyst at room temperature, respectively. The values are consistent with the values reported in literature (Thompson, 1974). Fig.…”

Section: G Sivaramaiahsupporting

confidence: 93%

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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The thermal properties such as Gibbs free energy, activation energy, entropy and enthalpy have been evaluated from the absolute number of spins of E 1 ' in gamma-ray-irradiated and as-is amethysts. It is for the first time to calculate the above properties for E 1 ' in amethyst. The Gibbs free energy of E 1 ' increases with the decrease of temperature from 296 K to 90 K. The activation energy and pre-exponential coefficients of E 1 ' have been evaluated from the logarithmic number of spins and the reciprocal of temperature plot. The Curie temperature and Curie constant of E 1 ' have been evaluated from the reciprocal of magnetic susceptibility and temperature plot. The exchange field, exchange integral and exchange interaction energy have been evaluated from the Curie temperature.

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Section: G Sivaramaiahsupporting

confidence: 93%

Electron Spin Resonance Study of E<SUB>1</SUB>' in Natural and #947;-ray-irradiated Amethyst

Sivaramaiah¹

2014

Proceedings of the Indian National Science Academy

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“…and -1496.73_+3.41 kcal tool -1 at 298 ~ Table 2 lists our values of enthalpy and Gibbs energy of formation at 298.15 K along with those of Hays (1967), as cited in Robie and Waldbaum (1968), and Thompson (1974) The differences in these A H ~ and A G o may seem insignificant when compared with the total values. They are extremely important, however, when calculating equilibria in solid-solid reactions for which A S and A V are small.…”

Section: Enthalpies and Gibbs Energies Of Formationmentioning

confidence: 81%

Application of new thermodynamic data to grossular phase relations

Perkins

Essene

Westrum

et al. 1977

Contr. Mineral. and Petrol.

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Recent low temperature, adiabatic calorimetric heat capacity measurements for grossular have been combined with DSC measurements to give entropies up to 1000 K. In conjunction with enthalpy of solution values for grossular, these data have yielded AH~f (298.15 K) and AG~ K) values of-1583.2 _ 3.5 and-1496.74 +_ 3.7 kcal mol-1 respectively. For 15 reactions in the CaO-A1203-SiO2-I-I20 system, thermodynamically calculated P-T curves have been compared with experimental reversals and have shown good agreement in most cases. Calculations indicate that gehlenite is probably totally disordered. Estimates of zoisite and lawsonite entropies are consistent with the phase equilibrium and grossular data, but estimates of the entropies of pyrope and andradite show large discrepancies when compared with experimental reversals.

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“…Salje et al [169] also reported different possibilities for the entropy difference at 298.15 K: 17.97 J Á mol À1 Á K À1 between a fully ordered and a fully disordered albite and 14.37 J Á mol À1 Á K À1 for a more realistic case between a slightly disordered and a slightly ordered albite. However, the enthalpy of transformation for low-albite to high-albite (usually heat treated low-albite, thus maybe analbite) has been measured by different authors [166,[176][177][178][179][180][181] using low-temperature acid solution calorimetry or high-temperature oxide solution calorimetry. These experimental data are in a relative good agreement, within 2500 J of the average value 11697.3 J Á mol À1 , which was adopted in this work for the low-albite to high-albite transformation.…”

Section: Entropymentioning

confidence: 99%