Thermodynamic properties of fluorapophyllite-(k) and hydroxylapophyllite-(k)

Thermochemical study of natural minerals of the apophyllite group: fluorapophyllite-(K) KCa4[Si8O20]F . 8H2O (Maharashtra, India) (I) and hydroxylapophyllite-(K) KCa4[Si8O20]OH . 8H2O (Norilsk, Russia) (II) were performed on a high-temperature heat-flux microcalorimeter Tian–Calvet “Setaram” (France) using the melt solution calorimetry method. The first data on the enthalpies of formation from the elements for the minerals studied are obtained: -13 205±13 kJ/mol (I) and -13 054±20 kJ/mol (II). The values of their standard entropies and Gibbs energies of formation are estimated.

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Thermochemical study of sodium and sodium-calcium amphibols

Геохимия ◽

10.31857/s0016-7525645520-528 ◽

2019 ◽

Vol 64 (5) ◽

pp. 520-528

Author(s):

L. P. Ogorodova ◽

I. A. Kiseleva ◽

M. F. Vigasina ◽

Yu. D. Gritsenko ◽

I. A. Bryzgalov ◽

...

Keyword(s):

Kola Peninsula ◽

Solution Calorimetry ◽

Enthalpies Of Formation ◽

Thermochemical Study ◽

Massif Central ◽

Calvet Microcalorimeter ◽

Gibbs Energies ◽

Sodium Calcium ◽

Isomorphic Series ◽

End Members

A thermochemical study of six natural sodium and sodium-calcium amphiboles was carried out using the high-temperature melt solution calorimetry on a Tian-Calvet microcalorimeter. The enthalpies of formation from the elements have been obtained for arfvedsonites: K0.5(Na1.5Ca0.5)(Mg4.0Fe0.93+Al0.1)[Si8.0O22](OH)2 (Inaglinsky Massif, Central Aldan, Russia) (-11626.6 ± 8.9 kJ/mol), (Na0.5K0.1)(Na1.6Ca0.4)(Mg3.6Fe0.42+Fe0.83+Al0.2)[Si8.0O22](OH)2 (Khibiny Massif, Kola Peninsula, Russia) (-11520.8 ± 14.6 kJ/mol) and (Na0.7K0.3)Na2.0(Fe4.02+Fe0.63+Mn0.1Ti0.1Al0.2)[Si8.0O22](OH)2 (Katuginskoe deposit, Transbaikalia, Russia) (-11384.7 ± 17.1 kJ/mol); for riebeckites: Na2.0(Mg2.5Fe0.52+Fe1.53+Al0.5)Si8O22(OH)2 (Kumula deposit, Central Kazakhstan) (-10791.0 ± 10.1 kJ/mol) and Na2.0(Mg0.9Fe2.12+Fe1.93+Al0.1)[Si8O22](OH)2 (Krivoy Rog, Ukraine) (-10260.8 ± 10.9 kJ/mol) and richterite (Na0.7K0.3)(Ca1.2Na0.8)(Mg4.6Fe0.42+)[Si7.8Al0.2O22](OH)2 (Kovdorsky Massif, Kola Peninsula, Russia) (-12154.2 ± 9.7 kJ/mol). The values of the standard entropies, enthalpies, and Gibbs energies of formation are estimated for the end members of isomorphic series: arfvedsonite – magnesioarfvedsonite, riebeckite – magnesioriebeckite and richterite – ferrochichthite.

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Thermodynamic properties of zirconium chlorides II. The standard molar enthalpies of formation, the low-temperature heat capacities, the standard molar entropies, and the standard molar Gibbs energies of formation of zirconium monochloride, zirconium dichloride, and zirconium tetrachloride

The Journal of Chemical Thermodynamics ◽

10.1016/0021-9614(89)90049-9 ◽

1989 ◽

Vol 21 (7) ◽

pp. 677-685 ◽

Cited By ~ 5

Author(s):

M.E. Efimov ◽

I.V. Prokopenko ◽

V.A. Medvedev ◽

V.I. Tsirelnikov ◽

G.A. Berezovskii ◽

...

Keyword(s):

Low Temperature ◽

Thermodynamic Properties ◽

Heat Capacities ◽

Enthalpies Of Formation ◽

Zirconium Tetrachloride ◽

Gibbs Energies ◽

Temperature Heat

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Thermodynamic properties of montechellite

Геохимия ◽

10.31857/s0016-752564121274-1280 ◽

2019 ◽

Vol 64 (12) ◽

pp. 1274-1280

Author(s):

L. P. Ogorodova ◽

Yu. D. Gritsenko ◽

M. F. Vigasina ◽

A. Yu. Bychkov ◽

D. A. Ksenofontov ◽

...

Keyword(s):

High Temperature ◽

Gibbs Energy ◽

Solution Calorimetry ◽

Thermochemical Study ◽

Gibbs Energy Of Formation ◽

Calvet Microcalorimeter ◽

Magnesium Orthosilicate ◽

Calcium And Magnesium ◽

The Enthalpy Of Formation ◽

Energy Of Formation

A thermochemical study of natural calcium and magnesium orthosilicate ─ monticellite (Ca1.00Mg0.95)[SiO4] (Khabarovsk Territory, Russia) was carried out on the Tian-Calvet microcalorimeter. The enthalpy of formation from the elements fHоel(298.15 K) = -2238.4 4.5 kJ / mol was determined by the method of high-temperature melt solution calorimetry. The enthalpy and Gibbs energy of formation of monticellite of the theoretical composition of CaMg[SiO4] are calculated: fH0el(298.15 K) = -2248.4 4.5 kJ/mol and fG0el(298.15 K) = -2130.5 4.5 kJ/mol.

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