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Heat capacities of three ketohexoses in monosaccharides, D -fructose, D -psicose, and D -tagatose, were measured for crystalline states in the temperature range from 13.8 K to 330 K by adiabatic calorimetry. Their standard thermodynamic functions were estimated from the measured molar heat capacities. A spectral analysis using Kieffer’s model was applied to the heat capacities to rationalize the relation among them in terms of intra- and intermolecular hydrogen bond in crystal.

The formation of globular associate on cooling, which was previously claimed on the basis of small dielectric constant, is supported through measuring X-ray scattering from dicyclohexylmethanol (DCHM). Radial distribution function of the DCHM molecules exhibits strong temperature dependence between 65 °C and 130 °C in contrast to a little change in that of tricyclohexylmethanol (TCHM), which is similar to DCHM but essentially non-associating in experimental conditions (95–160 °C).

Greigite, a ferrimagnetic iron sulfide Fe(II)Fe(III)2S4, is thought to have played an essential role in chemical evolution leading to the origin of life. Greigite contains a [4Fe–4S] cluster-like structure and has been synthesized in the laboratory by liquid-state reactions. However, it is unclear how greigite can be synthesized in nature. Herein, we show that greigite is synthesized by the solid–gas reaction of Fe(III)-oxide-hydroxides and H2S. We discovered that the hyperthermophilic hydrogenotrophic methanogen Methanocaldococcus jannaschii reduced elemental sulfur, and the resulting sulfide generated greigite from hematite. The time course and pH dependence of the reaction respectively indicated the involvement of amorphous FeS and H2S as reaction intermediates. An abiotic solid–gas reaction of hematite and H2S (g) under strictly anaerobic conditions was developed. The solid–gas reaction fully converted hematite to greigite/pyrite at 40–120 °C within 12 h and was unaffected by the bulk gas phase. Similar abiotic reactions occurred, but relatively slowly, with aqueous H2S in acidulous liquids using hematite, magnetite, or amorphous FeO(OH) as starting materials, suggesting that greigite was extensively produced in the Hadean Eon as these Fe(III)-oxide-hydroxides were shown to be present or routinely produced during that era. Surprisingly, the obtained greigite induced methanogenesis and growth of hydrogenotrophic methanogens, suggesting that the external greigite crystals enhanced reactions that would otherwise require enzymes, such as [4Fe–4S] cluster-harboring membrane-bound hydrogenases. These data suggested that the greigite produced by the solid–gas and solid–dissolved gas reactions was bioactive.

Phase transition behavior of 1,2-bis(4′- n -hexyloxybenzoyl)hydrazine (BABH(6)) was studied by differential scanning calorimetry (DSC) and polarizing microscopy. While the DSC trace above melting temperature is consistent with the existing report, it is not for crystalline states. A number of tiny and spiky anomalies was observed in the first cooling run whereas the number of anomalies decreases, and finally disappeared in repeated runs. Microscopic observation revealed that the tiny and spiky anomalies arise from collapsing of crystals. When the sample was cooled from the cubic phase (430 K), the tiny and spiky anomalies revived on the cooling process, which can be ascribed to the liquid-crystallinity of the cubic phase.

To establish the alkyl-chain-length dependences of thermodynamic properties of typical ionic liquids [Cnmim][Tf2N], the heat capacities of compounds with n = 2 and 18 were measured by adiabatic calorimetry. The comparison with other ionic liquids and typical molecular substances reveals that the low melting point of [Cnmim][Tf2N] with a short alkyl chain mainly originate in the large fusion entropy arising from the low entropy of the crystalline phase.

Thermal expansions of un-doped ceria and rare earth-doped ceria (Ce 1− x M x O 2− x /2 , M = La, Sm, Dy, Yb) were measured in the temperature range from 100 to 800 K by TMA. Debye temperatures of these compounds were measured at room temperature by an ultrasonic pulse method. The thermal expansion coefficients of rare earth-doped CeO 2 increased with increasing ionic radius of doped ions and its M content expect Dy ion. The Debye temperature of rare earth-doped ceria estimated from the longitudinal and transverse sonic wave velocities decreased with increasing M content, probably due to generation of oxygen vacancy by doping the rare earth elements. The relation between thermal expansion coefficient and Debye temperature was discussed.

Zr 1− x Lu x W 2 O 8− y solid solutions were newly synthesized by a solid sate reaction method. X-ray diffraction (XRD) experiments from 90 to 560 K revealed that the solid solutions were of a single phase up to x = 0.04 and showed a negative thermal expansion. Order–disorder phase transition temperatures ( T trs ) and saturated order parameters ( η s ) associated with WO 4 orientational order were determined from the XRD results. The linear relationship between the normalized T trs and η s obtained for Zr 1− x M x W 2 O 8− y (M = Sc, Y, In) in our previous study was also found for Zr 1− x Lu x W 2 O 8− y . A heat capacity anomaly due to the order–disorder phase transition was detected for Zr 0.96 Lu 0.04 W 2 O 8− y by a relaxation calorimeter. T trs of the solid solutions drastically decreased with increasing Lu content. The drastic suppression of T trs can be explained by the model assuming the existence of a local nano-region including the WO 4 pairs having the orientational disorder.

High-resolution core-level photoemission and core-level absorption spectroscopy of a series of Fe intercalates, Fe x NbS 2 ( x = 0, ∼1/4 and ∼1/3) has been performed to investigate changes in the electronic structures induced by the intercalation. From the evolution of spectral line shapes from the host material, we obtained important information on the electronic and geometric structures specific to particular atomic sites upon intercalation with Fe. The spectra of Fe core-levels also show x dependence, suggesting appreciable mixing of orbitals between Fe and NbS 2 .

Electrical conductivity of MAl 0.97 Zn 0.03 O 3− y (M=La, Sm, Eu, Gd, Dy) and Eu 0.9 Ca 0.1 Al 0.97 Zn 0.03 O 3− y was measured at temperatures from 773 to 1273 K and oxygen partial pressures from 10 3 to 10 5 Pa. Effect of ionic radius of M ion in A site on the electrical conductivity of MAl 0.97 Zn 0.03 O 3− y (M=Rare earth) was discussed. From the oxygen partial pressure dependence of electrical conductivity, MAl 0.97 Zn 0.03 O 3− y (M=La, Sm, Eu) and Eu 0.9 Ca 0.1 Al 0.97 Zn 0.03 O 3− y were a mixed conductor of oxide ion and hole at temperatures from 773 to 1273 K. Oxide ion conductivity of doubly doped Eu 0.9 Ca 0.1 Al 0.97 Zn 0.03 O 3− y was one order of magnitude large than that of a singly doped EuAl 0.97 Zn 0.03 O 3− y . Oxide ion conductivity of Eu 0.9 Ca 0.1 Al 0.97 Zn 0.03 O 3− y was compared with those of typical oxide ion conductors and was discussed from the point of view of the tolerance factor for the perovskite structure.

Heat capacities of single crystals of Fe x NbS 2 ( x =0.159, 0.281, 0.309 and 0.325) were measured at temperatures from 1.8 to 100 K. Heat capacity anomalies were observed in all of the single crystals. Both Fe 0.325 NbS 2 and Fe 0.309 NbS 2 underwent the successive three magnetic phase transitions around 40 K. The successive phase transitions originate in the √3 a ×√3 a superstructure in-plane of Fe 1/3 NbS 2 . A phase diagram of Fe x NbS 2 system was established from the obtained temperatures of magnetic phase transition and spin-glass like transition.

Ca 1− x Pr x MnO 3− δ ( x =0, 0.05, 0.15, 0.1, 0.2, 0.4, 0.67; δ =0.02) samples were prepared by a solid-state reaction method. X-ray diffraction analysis showed that all samples prepared were of single phase with orthorhombic structure. Electrical resistivity measurements from room temperature to 1300 K showed that a metallic conducting tendency dominated at high temperatures. The hopping nature of the charge carriers was well interpreted in the framework of polaron theory. The Seebeck coefficient was measured in the same temperature interval, and its concentration dependence was analyzed using the high-temperature (HT) thermopower theory proposed by Marsh–Parris. The thermal conductivity and the figure of merit of the prepared samples were also compared with those of other similar perovskite compounds. The observed figure of merit of the sample with x =0.15 was Z =1.5×10 −4 K −1 at T =1100 K, indicating a good potential for application as a HT thermoelectric material.

Thermodynamic properties of negative thermal expansion materials, ZrW2O8 substituted for Zr site, were studied by X-ray diffraction and heat capacity measurements. Effect of substituted ions on lattice parameters of these materials was discussed from the viewpoint of ionic radius of substituted and host ions, and of oxygen defect. The entropy of α-to-β phase transition in Zr1−xHfxW2O8 series (x=0, 0.5 and 1) was the same value of 2.1 J K−1 mol−1. The normalized 3 1 0 diffraction peaks in Zr1−xHfxW2O8 (x=0 and 0.5) and Zr0.98Sc0.02W2O8−y, as an indicator of the order parameter, followed the universal curve against (T−Ttrs)/Ttrs, where Ttrs is the transition temperature. These results suggest that these materials have the same order–disorder phase transition mechanism. The abrupt decrease in transition temperatures of Zr1−xMxW2O8−y (M=Sc, In and Y), compared to that of Zr1−xHfxW2O8, can be explained by the decrease of ordering in α-phase due to oxygen defect.

Heat capacity of ZrW2O8 was measured in the (1.8 to 483) K temperature range by using two adiabatic and a commercial relaxation calorimeters. Standard thermodynamic functions of ZrW2O8 were estimated from the measured molar heat capacity. A large λ-type anomaly of heat capacity due to an order–disorder phase transition was observed at T=(440±0.5) K. The enthalpy and entropy of phase transition were determined to be (1.56 ± 0.01) kJ · mol−1 and (4.09 ± 0.03) J · K−1 · mol−1, respectively. The magnitude of the entropy of transition supports the order–disorder mechanism previously suggested by the present authors.

Zr1−xMxW2O8−y (M=Sc, In and Y) solid solutions substituted up to x=0.04 for Zr(IV) sites by M(III) ions were synthesized by a solid-state reaction. X-ray diffraction experiments from 90 to 560 K revealed that all solid solutions had a cubic crystal structure and showed negative thermal expansion coefficients. The lattice parameters of Zr1−xMxW2O8−y were smaller than that of ZrW2O8 probably due to oxygen defects, though the ionic radii of substituted M3+ ions were larger than that of Zr4+. Order–disorder phase transition temperatures of the substituted samples drastically decreased in the order of Y, In and Sc compared to the percolation theory, and decreased with increasing M content.

Electrical conductivity of SmAlO 3 substituted by Ni, Mg or Zn ions for Al site was measured as a function of temperature. The electrical conductivity of doped SmAl 0.95 M 0.05 O 3− x (M=Ni, Mg and Zn) was about three to four orders of magnitude larger than that of undoped SmAlO 3 and increased in the order of Ni, Mg and Zn ions. Effect of ionic radius of doped ions on the electrical conductivity of SmAl 0.95 M 0.05 O 3− x (M=Ni, Mg and Zn) was discussed. It has been found from the oxygen partial pressure dependence of electrical conductivity that SmAl 0.95 Zn 0.05 O 3− x was a mixed conductor of oxide ion and hole from 973 to 1273 K. Transport number of oxide ion in SmAl 0.95 Zn 0.05 O 3− x increased with decreasing temperature. Oxide ion conductivity of SmAl 0.95 Zn 0.05 O 3− x was compared with those for typical oxide ion conductors and was discussed from the point of view of a tolerance factor.

Structural and thermal properties of Fe-doped lithium manganese oxides, Li 0.9 Mn 2− x Fe x O 4 and LiMn 2− x Fe x O 4 , were studied by means of X-ray diffraction (XRD), Mossbauer spectroscopy, DSC and TGA methods. Mossbauer spectroscopy measurements revealed that the iron in Fe-doped samples existed as high spin Fe 3+ (main component) and Fe 4+ (minor component) in noncubic octahedral site (16d). Lattice constants of Fe-doped samples increased with increasing doped iron contents, probably due to the substitution of Fe 4+ with large ionic radius for Mn 4+ with small ionic radius. Disappearance of endothermic peak due to Jahn–Teller effect of Mn 3+ and Fe 4+ around room temperature for Li 0.9 Mn 2− x Fe x O 4 with higher iron contents reflects mainly the substitution of Fe 3+ for Mn 3+ . Starting temperature of weight loss for LiMn 2− x Fe x O 4 determined by TGA measurements increased with increasing iron contents and weight loss at constant temperature decreased. Doped iron of the samples seems to play an important role in the thermal stability of the spinel structure at high and low temperatures.

Heat capacity of HfW2O8 was measured from 1.8 to 330 K. Gruneisen function of HfW2O8 was obtained between 80 and 330 K from the heat capacity and other thermal data. Effective phonon density of states was determined through an analysis of the heat capacity of HfW2O8 assuming one Debye, two Einstein and two rectangular type functions. The mode Gruneisen parameters were estimated from these phonon distribution. It is found that two low-energy Einstein modes at 3–6 meV have large negative model Gruneisen parameters, resulting in the negative thermal expansion.

Thermal expansion and mechanical properties of Ce 1− x Hf x O 2 ( x =0–0.10) solid solutions were measured from 100 to 850 K by TMA and from 180 to 303 K by ultrasonic pulse methods, as a function of temperature and hafnium concentration. Using these measured values and reported specific heat capacities ( C p ) at 298.15 K, Gruneisen parameters ( γ ) of Ce 1− x Hf x O 2 were calculated from the thermodynamic relation γ =3 αVK a / C p . Then heat capacities C p of Ce 1− x Hf x O 2 ( x =0–0.10) at temperatures from 150 to 800 K were calculated by using the equation C p =3 αVK a / γ . The calculated C p of undoped CeO 2 was in reasonable agreement with the reported value over a wide temperature range. Thus, it seems to be reasonable to derive heat capacities of Ce 1− x Hf x O 2 solid solutions as well as CeO 2 by using this method.

Heat capacities and magnetic susceptibilities of single crystals of Fe x NbS 2 ( x =0.199 and 0.239) were measured at temperatures from 1.8 to 300 K and from 5 to 300 K, respectively. For Fe 0.199 NbS 2 , anomalies in the heat capacity and magnetic susceptibility were observed at 36 and 39 K, respectively. A noteworthy difference between field-cooled χ ‖ (FC) and zero field-cooled χ ‖ (ZFC) below 60 K, supports the evidence of a spin-glass state for Fe 0.199 NbS 2 . An anomaly in the heat capacity was observed for Fe 0.239 NbS 2 at 146.5 K, whereas the magnetic susceptibility displayed a maximum at 151 K, corresponding to an antiferro–paramagnetic phase transition. Heat capacity data of single crystal of Fe 0.239 NbS 2 were in good agreement with those of powdered sample at temperatures excluding an order–disorder phase transition. The experimental excess entropy of antiferro–paramagnetic phase transition was calculated to be 8.4 J K −1 (mol Fe) −1 for Fe 0.239 NbS 2 and compared with the theoretical value calculated on the basis of entropy analysis.

Heat capacities of orthoferrites, ErFeO 3 and TmFeO 3 , have been measured below room temperature by adiabatic calorimetry. A broad but definite anomaly due to the spin reorientation phenomenon was successfully detected in the expected temperature range (ca. 90 K). The results are compared with a vast anomaly reported for YbFeO 3 . The temperature dependence of the electric quadrupole splitting of the Fe nuclear levels was determined by Mossbauer spectroscopy through the spin reorientation. A heat capacity anomaly centered at 3.60 K due to the magnetic ordering of Er 3+ ions was clearly detected. Some Schottky anomalies were resolved and energy splittings involved were roughly estimated. Some thermodynamic functions are derived and tabulated.

To study the anisotropic Josephson-vortex dynamics in the d-wave superconductors, the interplane resistance has been measured on layered organic superconductors κ ‐ ( ET ) 2 Cu ( NCS ) 2 and β ‐ ( BDA ‐ TTP ) 2 SbF 6 under magnetic fields precisely parallel to the conducting planes. For κ ‐ ( ET ) 2 Cu ( NCS ) 2 , in-plane angular dependence of the Josephson-vortex flow resistance is mainly described by the fourfold symmetry and dip structures appear when the magnetic field is applied parallel to the b- and c-axes. The obtained results have a relation to the d-wave superconducting gap symmetry. However, the absence of in-plane fourfold anisotropy was found for β ‐ ( BDA ‐ TTP ) 2 SbF 6 . The different anisotropic behavior is discussed in terms of the interlayer coupling strength.

TG-DTA and high-temperature X-ray diffraction measurements were carried out at temperatures from room temperature to 1623 K under various CO 2 partial pressures to study the formation of SrCe 1− y Eu y O 3− x from SrCO 3 , CeO 2 and Eu 2 O 3 and also the reaction of the perovskite, SrCe 1− y Eu y O 3− x , with CO 2 gas. For the formation reaction of SrCe 1− y Eu y O 3− x sample, two endothermic reactions are observed at 1198 and 1309 K in DTA curves. The former reaction corresponds to the crystal structural change of the carbonate from orthorhombic to hexagonal phase, whereas the latter one is the endothermic formation reaction of the perovskite together with the decomposition of SrCO 3 . From the reaction of the perovskite with CO 2 gas, it is found that the Eu-doped SrCeO 3 sample is less stable than the undoped sample at constant temperature, because of smaller tolerance factor of the former.

Configurational entropy due to structural disorder in complex crystals is considered in some details. It is reminded that motional correlation and equivalence of plural entities (such as molecule or group) have potentially serious effects on the entropy. Possible appearance of entropy plateaus in its temperature dependence is suggested.

The heat capacity of crystalline 4,4‴-difluoro- p -quaterphenyl was measured between 8 and 303 K by adiabatic calorimetry. A broad heat-capacity anomaly was found at 200.5 ± 0.5 K and attributed to a phase transition associated with molecular twisting. Some thermodynamic properties including those concerning the phase transition are reported.

A deuterium-induced phase transition has been discovered in a molecular crystal of tolane- d 10 by powder X-ray diffraction and differential scanning calorimetry (DSC) experiments. The phase transition is of first order. DSC measurements on solid binary solutions of tolane- h 10 and tolane- d 10 have shown that there is a critical point on the temperature-composition phase diagram of this binary system.

The heat capacities of crystalline trans-azobenzene and trans-stilbene were measured by adiabatic calorimetry. No anomalies were detected in both compounds at any temperature regions where possible phase transitions have been previously suggested. Anomalies due to glass transitions were observed at about 170 and 110 K for trans-stilbene and trans-azobenzene, respectively. The magnitude of the heat capacity jump at the transition is analysed and the transitions are attributed to the freezing of the intramolecular crankshaft motion. Thermodynamic functions are tabulated for trans-azobenzene.

The heat capacity of 4,4″-difluoro- p -terphenyl was measured between 8 and 303 K by adiabatic calorimetry. A phase transition associated with molecular twisting was observed as a sharp peak at (127.05 ± 0.05) K. The enthalpy and the entropy of transition were determined as (180 ± 20) J mol −1 and (1.41 ± 0.15) J K −1 mol −1 , respectively. It is pointed out that this phase transition lies in the border region between an order-disorder and displacive-type transition under normal pressure. The apparatus used for calorimetry is described.

The heat capacity of crystalline 4,4‴-difluoro- p -quaterphenyl was measured from 8 K to 303 K by adiabatic calorimetry. A broad anomaly was detected between 140 and 250 K and attributed to a structural phase transition associated with molecular twisting. The temperature, the enthalpy and the entropy of transition were determined as (200.5 ± 0.5) K, (322 ± 20) J·mol −1 and (1.65 ± 0.10) J·K −1 ·mol −1 , respectively. The properties of the transition are compared with those of unsubstituted and fluorine-substituted p -polyphenyls (of two to four benzene rings in a molecule) in the light of a unified model of displacive and order-disorder types of structural phase transition.

Low-temperature X-ray diffraction experiments were performed on 4,4″-difluoro-p-terphenyl (DFTP) and 4,4‴-difluoro-p-quaterphenyl (DFTP). The structure analyses were performed for the high- temperature phases and the librational motion of the benzene rings was analyzed. The super-lattice reflections were found in DFQP below about 200 K on the same positions as the low-temperature phase of p-quaterphenyl. In DFTP, the satellite reflections with small wavevector component δc (about 1 6 ) along the c∗-axis were found below the transition temperature.

Heat capacity of ZrW 2 O 8 has been measured as a function of temperature from 340 to 550 K. An anomaly in heat capacity corresponding to the α-to-β structural phase transition was clearly detected for the first time around 431 K. The transition temperature was determined to be 431±1 K , and the minimum bound of the transition entropy as 2.1 J K −1 mol −1 . Although this value is smaller than the theoretical one of R ln 2 (=5.8 J K −1 mol −1 ), the phase transition is considered to be of the order–disorder type.

We have measured the electrical resistivity and the Hall coefficient of the metallic intercalation compounds Fe x NbS 2 (0.159 ≤ x ≤ 0.325). The magnetic scattering by the spin fluctuation of Fe superstructure was observed in the electrical resistivity. The anomalous Hall coefficient due to the asymmetric carrier scattering changes its sign from positive to negative at the critical content x=1/4. These results indicate that the electronic properties of the system strongly depend on the spin ordering of the Fe ions in the van der Waals gap.