An experimental method is described for determining the low-temperature heat capacity (C(p)) of mg-sized powder samples using Quantum Design "Physical Properties Measurement System" (PPMS). The contained in an Al pan as ∼1 mm thick compressed layer. sample not mixed with Apiezon N grease, compared to other methods. Thus, it contaminated and can be used further study. This necessary that are only available tiny amounts. To demonstrate various samples, all insulating nature, were studied...

Abstract Plagioclase undergoes complex exsolution and ordering phase transition processes during their evolution in nature, this has hindered attempts to define simple trends relating the major peaks of Raman spectra with composition. Here, peak position linewidth features have been calibrated for a set 20 plagioclases, spanning from albite anorthite composition, symmetry states that were already well characterized. Point group is most important factor determining behaviour though C , I P...

The thermodynamic model of the two-feldspar thermometer has been revised. From recent enthalpy and volume measurements in (Na,Ca)- (K,Ca)-feldspar binaries, new interaction parameters have derived previous ones updated. Entropy fitted to phase equilibrium data Seck (1971) Elkins Grove (1990). two sets could be suitably combined into one. Ideal Ab, Or, An activities expressed terms both molecular mixing Al-avoidance models.

Abstract Copiapite-group minerals are common products of weathering sulfides, especially pyrite and pyrrhotite. They have a general formula AFe3+4(SO4)6(OH)2·20H2O all crystallize in the triclinic crystal system (space group P). In this work, we determined thermodynamic properties copiapite (A = Fe2+), ferricopiapite 2/3Fe3+), magnesiocopiapite Mg), aluminocopiapite 2/3Al). Enthalpies formation were calculated from enthalpies dissolution 5 mol/dm3 HCl (measured by acid-solution calorimetry)...

<title>Abstract</title> In this work, we measured heat capacity and enthalpy of formation synthetic mimetite phases with composition Pb₅(AsO₄)₃Cl_0.8(CO₃)_0.1 Pb₅(AsO₄)₃F, Pb₅(AsO₄)₃Br_0.8(CO₃)_0.1, Pb₅(AsO₄)₃OH_0.86(CO₃)_0.07,...

The internal energies and entropies of 21 well-known minerals were calculated using the density functional theory (DFT), viz. kyanite, sillimanite, andalusite, albite, microcline, forsterite, fayalite, diopside, jadeite, hedenbergite, pyrope, grossular, talc, pyrophyllite, phlogopite, annite, muscovite, brucite, portlandite, tremolite, CaTiO3-perovskite. These thermodynamic quantities then transformed into standard enthalpies formation from elements enabling a direct comparison with...

The high-temperature heat capacity of fayalite was reinvestigated using drop and differential scanning calorimetry. resulting data together with calorimetry taken from the literature were analyzed yielding CP J/(mol·K) = -584.388 + 129 440·T−1 - 3.84956·107·T−2 4.10143·109·T−3 98.4368·ln(T). This new polynomial is recommended for calculating phase equilibria involving at mantle conditions. Using thermal expansion coefficient isothermal bulk modulus literature, isochoric calculated in CV...

The thermodynamics of disordering in Cu3Au have been investigated by measuring the heat capacity samples with different degrees long- and short-range order between T = 5 720 K using relaxation differential scanning calorimetry. capacities L12-ordered fcc-disordered show similar behaviour at low temperatures (<300 K). They deviate positively from linear combination end-member ∼30 160 K. However, small differences two exist, as disordered sample has a larger producing vibrational entropy ∼0.05...

Low- and high-temperature heat capacities for a series of synthetic high structural state plagioclase crystals (Ab-An) were measured using both relaxation calorimeter differential scanning calorimeter. The measurements performed at temperatures between 5 800 K on milligram-sized polycrystalline samples that had been characterized in previous study. data show positive excess mixing below 300 with maximum value ~2 J/(mol·K). Below ~70 K, the exceed two standard deviations are thus significant....

The heat capacity of three synthetic polycrystalline almandine garnets (ideal formula Fe3Al2Si3O12) and one natural almandine-rich single crystal was measured. samples were characterized by optical microscopy, electron microprobe analysis, X-ray powder diffraction, Mössbauer spectroscopy. Measurements performed in the temperature range 3 to 300 K using relaxation calorimetry between 282 764 DSC methods. All show a prominent λ-type heat-capacity anomaly at low temperatures resulting from...

The paper presents new calorimetric data on the excess heat capacity and vibrational entropy of mixing Pt-Rh Ag-Pd alloys. results latter alloy are compared to those obtained by calculations using density functional theory. extent these binaries some already investigated binary mixtures is related differences end-member volumes bulk moduli. These quantities used roughly represent changes bond length stiffness in substituted substituent polyhedra due compositional changes, which assumed be...

The enthalpies of formation synthetic MgSO4·4H2O (starkeyite) and MgSO4·3H2O were obtained by solution calorimetry at T=298.15 K. resulting from the elements are (starkeyite)=−2498.7±1.1 kJ·mol−1 (MgSO4·3H2O)=−2210.3±1.3 kJ·mol−1. standard entropy starkeyite was derived low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in temperature range 5 K<T<300 K: (starkeyite)=254.48±2.0 J·K−1·mol−1. Additionally, differential scanning (DSC) Perkin...

NASICON-based solid electrolytes with exceptionally high Na-ion conductivities are considered to enable future all solid-state battery technologies. Despite 40 years of research the interrelation between crystal structure and conduction is still controversially discussed far from being fully understood. In this study, microcontact impedance spectroscopy combined single X-ray diffraction, differential scanning calorimetry applied tackle question how bulk conductivity σbulk sub-mm-sized flux...

In spite of the amount research that has been done on grossular, Ca3Al2Si3O12, there is still uncertainty regarding its exact thermodynamic properties. Because insufficient sample characterization in various published calorimetric studies, it difficult to analyze conflicting CP and S○ results. To resolve discrepancies, a detailed systematic multi‑method investigation was undertaken. Three synthetic grossular samples four natural grossular‑rich garnets were characterized by optical...

Poly(methyl methacrylate) (PMMA) is a very versatile polymer which used as glass substitute or an economical alternative to polycarbonate for many types of important applications, due its particular physical properties.

The low-temperature heat capacity behavior of synthetic katoite, Ca3Al2H12O12, was investigated for the first time using microcalorimetry. sample synthesized hydrothermally in Au capsules at 250 °C and 3 kb water pressure. X-ray powder measurements show that about 98-99% katoite obtained. Heat capacities were measured with a commercially designed relaxation calorimeter between 5 300 K on milligram-sized around ambient temperatures differential scanning calorimeter. data are well behaved T <...