scholarly journals Thermochemical study of sodium and sodium-calcium amphibols

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.

scholarly journals Natural kaersutite: ftir, raman, thermal and thermochemical investigations

2019 ◽  
Vol 64 (6) ◽  
pp. 651-657
Author(s):  
L. P. Ogorodova ◽  
Yu. D. Gritsenko ◽  
M. F. Vigasina ◽  
L. V. Melchakova
Keyword(s):  
High Temperature ◽  
Gibbs Energy ◽  
Enthalpy Of Formation ◽  
Solution Calorimetry ◽  
Thermochemical Study ◽  
Calvet Microcalorimeter ◽  
Isomorphic Series ◽  
End Members ◽  
The Enthalpy Of Formation

A thermochemical study of the natural oxo-amphibole ─ kaersutite Na0.4K0.3(Ca1.6Na0.4)(Mg2.9Fe0.82+Al0.7Ti0.6Fe0.53+)[Si6.1Al1.9O22](OH)0.2O1.8.(alkaline basalts of Mongolia) was performed on a Tian-Calvet microcalorimeter. The enthalpy of formation from the elements ∆fH el0(298.15 K) = – 12102 ± 16 kJ/mol) was obtained by the method of high-temperature melt solution calorimetry. The entropy, enthalpy and Gibbs energy of the formation of the end-members of the isomorphic series kaersutite NaCa2Mg3TiAl[Si6Al2O22]O2 – ferri-kaersutite NaCa2Mg3TiFe3+[Si6Al2O22]O2 were estimated.

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

2019 ◽  
Vol 64 (7) ◽  
pp. 726-732
Author(s):  
L. P. Ogorodova ◽  
L. V. Melchakova ◽  
M. F. Vigasina ◽  
Yu. D. Grytsenko ◽  
D. A. Ksenofontov ◽  
...  
Keyword(s):  
Heat Flux ◽  
High Temperature ◽  
Thermodynamic Properties ◽  
Solution Calorimetry ◽  
Enthalpies Of Formation ◽  
Thermochemical Study ◽  
Gibbs Energies ◽  
Natural Minerals ◽  
Temperature Heat

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.

Thermodynamic properties of montechellite

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.

Energetics of rare-earth-doped hafnia

2007 ◽  
Vol 22 (4) ◽  
pp. 876-885 ◽  
Author(s):  
Petra Simoncic ◽  
Alexandra Navrotsky
Keyword(s):  
Rare Earth ◽  
Solid Solutions ◽  
Energy Difference ◽  
Solution Calorimetry ◽  
Interaction Parameters ◽  
Enthalpies Of Formation ◽  
Amorphous Phases ◽  
Oxide Melt ◽  
Local Structures ◽  
End Members

The enthalpies of formation of rare-earth (RE)-doped Hf1−xRExO2−x/2 solid solutions (RE = Sm, Gd, Dy, Yb; x = 0.25 to 0.62) with respect to the oxide end members, monoclinic HfO2 and C-type REO1.5, were determined using oxide melt solution calorimetry. The enthalpies of formation fit a function quadratic in composition. The strongly negative interaction parameters in all solid solutions confirm a strong tendency for short-range order. Though strongly negative for all systems, the interaction parameters become less negative with increasing ionic potential (decreasing RE radius). Crystallization energetics were investigated for amorphous coprecipitation products with x = 0.4. The energy difference between the crystalline (fluorite and pyrochlore) and amorphous phases decreases with decreasing dopant radius. This suggests that systems doped with small RE ions have more similar local structures in the fluorite and amorphous phases. These observations may result in a smaller kinetic barrier to recrystallization and account for the greater radiation resistance of materials with smaller RE cations.

scholarly journals Thermodynamics of Molybdenum Trioxide (MoO3) Encapsulated in Zeolite Y

2021 ◽  
Author(s):  
Xianghui Zhang ◽  
Andrew Strzelecki ◽  
Cody Cockreham ◽  
Vitaliy Goncharov ◽  
Houqian Li ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Zeolite Y ◽  
Formation Enthalpy ◽  
Solution Calorimetry ◽  
Metal Species ◽  
Enthalpies Of Formation ◽  
Host Interactions ◽  
Oxide Melt ◽  
High Temperature Oxide ◽  
Temperature Oxide

Zeolites with encapsulated transition metal species are extensively applied in the chemical industry as heterogenous catalysts for favorable kinetic pathways. To elucidate the energetic insights into formation of subnano-sized molybdenum trioxide (MoO) encapsulated/confined in zeolite Y (FAU) from constituent oxides, we performed a systematic experimental thermodynamic study using high temperature oxide melt solution calorimetry as the major tool. Specifically, the formation enthalpy of each MoO/FAU is less endothermic than corresponding zeolite Y, suggesting enhanced thermodynamic stability. As Si/Al ratio increases, the enthalpies of formation of MoO/FAU with identical loading (5 Mo-wt%) tend to be less endothermic, ranging from 61.1 ± 1.8 (Si/Al = 2.9) to 32.8 ± 1.4 kJ/mol TO (Si/Al = 45.6). Coupled with spectroscopic, structural and morphological characterizations, we revealed intricate energetics of MoO – zeolite Y guest – host interactions likely determined by the subtle redox and/or phase evolutions of encapsulated MoO.

Experimental thermochemical study of the enthalpies of formation and sublimation of isonicotinamide, picolinamide, nicotinamide, isonicotinamideN-oxide, and nicotinamideN-oxide. The dissociation enthalpies of the N–O bonds

2001 ◽  
Vol 33 (10) ◽  
pp. 1263-1275 ◽  
Author(s):  
Maria D.M.C. Ribeiro da Silva, ◽  
Jorge M. Gonçalves ◽  
Susana C.C. Ferreira ◽  
Luís C.M. da Silva ◽  
M.J. Sottomayor ◽  
...  
Keyword(s):  
Enthalpies Of Formation ◽  
Thermochemical Study

Titration Calorimetry

2008 ◽  
Author(s):  
José A. Martinho Simões ◽  
Manuel Minas da Piedade
Keyword(s):  
Heat Flow ◽  
Temperature Change ◽  
Solution Calorimetry ◽  
Enthalpies Of Formation ◽  
Titration Calorimetry ◽  
Enthalpy Of Reaction ◽  
Thermodynamic Cycles ◽  
First Case ◽  
Reaction Solution ◽  
Constant Rate

Titration calorimetry is a method in which one reactant inside a calorimetric vessel is titrated with another delivered from a burette at a controlled rate. This technique has been adapted to a variety of calorimeters, notably of the isoperibol and heat flow types. The output of a titration calorimetric experiment is usually a plot of the temperature change or the heat flow associated with the reaction or physical interaction under study as a function of time or the amount of titrant added. A primary use of titration calorimetry is the determination of enthalpies of reaction in solution. The obtained results may of course lead to enthalpies of formation of compounds in the standard state by using appropriate thermodynamic cycles and auxiliary data, as described in chapter 8 for reaction-solution calorimetry. Moreover, when reactions are not quantitative, both the equilibrium constant and the enthalpy of reaction can often be determined from a single titration run. This also yields the corresponding ΔrGo and ΔrSo through equations 2.54 and 2.55. Extensive use has been made of titration calorimetry as an analytical tool. These applications, which are outside the scope of this book, have been covered in various reviews. The historical development of titration calorimetry has been addressed by Grime. The technique is credited to have been born in 1913, when Bell and Cowell used an apparatus consisting of a 200 cm3 Dewar vessel, a platinum stirrer, a thermometer graduated to tenths of degrees, and a volumetric burette to determine the end point of the titration of citric acid with ammonia from a plot of the observed temperature change against the volume of ammonia added. The capabilities of titration calorimetry have enormously evolved since then, and the accuracy limits of modern titration calorimeters are comparable to those obtained in conventional isoperibol or heat-flow instruments. The titration procedures described in the literature can be classified as continuous or incremental, depending on the mode of titrant addition. In the first case the titrant is continuously introduced in the reaction vessel at a programmed (not necessarily constant) rate during a run.

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