Junichi Mochinaga

X-ray diffraction and Raman spectroscopic study on the short-range structure of molten CeCl3

Abstract The short-range structure of molten CeCl 3 at 1143 K was studied by means of X-ray diffraction and Raman spectroscopy, and the octahedral configuration of CeCl 6 3− was found to exist in molten CeCl 3 . Also discussed is the medium-range structure with some assumptions.

Electrical Conductivity of Molten NdCl3 ‐ KCl , NdCl3 ‐ NaCl , and NdCl3 ‐ CaCl2 Solutions

The electrical conductivities of molten NdCl{sub 3}-KCl, NdCl{sub 3}-NaCl, and NdCl{sub 3}-CaCl{sub 2} solutions were measured by means of a conventional ac technique. The conductivities were well represented as quadratic functions of temperature. The equivalent conductivities were derived and were represented well by an Arrhenius-type function of temperatures. In this paper electrical conduction in these melts is discussed on the basis of octahedral complex formation and clustering.

Short range structure of B2O3–Cs2O glasses analyzed by x‐ray diffraction and Raman spectroscopy

Structural analyses of pure B2O3, B2O3(90 mol%)–Cs2O (10 mol%) and B2O3 (80 mol%)–Cs2O (20 mol%) glasses were made by an x‐ray diffraction method and the effects of Cs2O addition were investigated on the short range structure of the glasses. Furthermore, Raman spectroscopic studies were applied to analyze the interatomic interactions between boron and oxygen atoms. Due to x‐ray diffraction, pure B2O3 was confirmed to have BO3 triangles which formed the so‐called boroxol ring structure. When Cs2O was added to B2O3, the boroxol ring structure still remained but some parts of BO3 triangles was definitely converted to BO4 tetrahedra. This result was also supported by Raman spectroscopic observations. The other important consequences were that a Cs atom was surrounded by six O atoms, and four Cs–O interatomic distances were about 3 A but two pairs 3.5 A, indicating that the distorted Cs–O octahedra might exist in the B2O3–Cs2O glasses. This spatial arrangement of Cs and O atoms was quite different from the cor...

Electronic polarizabilities of Tl+, Ag+, and Zn2+ ions estimated from refractive index measurements of TlNO3, AgNO3, and ZnCl2 melts

Refractive indices of TlNO3, AgNO3, and ZnCl2 ionic melts were measured by a goniometer method using visible light at nine wavelengths. The refractive indices of these pure melts were represented conveniently as functions of both temperature and wavelength by means of a two‐dimensional least squares method. According to the obtained formulas, the refractive indices were extrapolated to infinite wavelength so that the electronic polarizabilities of Tl+, Ag+, and Zn2+ ions in each pure melt were evaluated in terms of the Clausius–Mossotti equation to be 4.16, 2.07, and 0.78 A3 at 420 °C, respectively. It was made clear even in the molten state, by correlating the electronic polarizabilities of ions with the ionic radii, that the electronic polarizabilities were unequivocally governed by the electron configuration as well as being affected by the ionic radii.

Molar volume variation and ionic conduction in molten ErCl3NaCl and ErCl3KCl systems

Molar conductivities (Λ) of molten ErCl3NaCl and ErCl3KCl systems were evaluated using the data of molar volume, Vm, and conductivity, ϰ, which were measured as a function of the mole fraction of ErCl3 and temperature, by dilatometry and a conventional a.c. technique, respectively. The Λ values of molten ErCl3 were smaller than those of molten YCl3, in which a loose disordered network of edge-sharing octahedral units has been reported to exist. The Λ values of ErCl3NaCl and ErCl3KCl systems increased with decreasing ErCl3 concentration, x, and in the range x >4 0.25 the increment in Λ with x was much smaller than that in the range of x < 0.25. In a series of molten rare earth chlorides, Λ values have been found to be affected qualitatively by cationic radii and the types of linkage, that is, corner- or edge-sharing of octahedral units.

Internal Cation Mobilities in the Molten Binary Systems ( Y , La ) Cl3 and ( Y , Dy ) Cl3

Internal cation mobility ratios in the molten systems (Y, La)Cl 3 and (Y, Dy)Cl 3 have been measured at 1073 K by the Klemm method and the electrical conductivities of these systems have been measured by conventional ac techniques. From these studies and the data available on the densities of the pure melts, the internal mobilities, u, have been calculated; u La is greater than u y , while the ionic radius of La 3+ is greater than that of Y 3+ . On the other hand, u Y is slightly greater than u Dy , where the ionic radii are much the same and the mass of Y 3+ is much less than that of Dy 3+ . Internal mobilities of all the cations in both (Y, La)Cl 3 and (Y, Dy)Cl 3 systems decrease with increasing molar volume of the mixtures. The dominant electrically conducting cationic species are conjectured to be the nonassociated rare-earth cations.

X-Ray Diffraction Study on the Local Structure of Molten ErCl3

Abstract The short range structure of molten ErCl3 at 1053 K was investigated by X-ray diffraction. The nearest neighbour distance of Er3+-Cl- and the coordination number of Cl- around Er3+ were estimated to be 2.63 Å and 5.8 Å, respectively, and the Er3+-Er3+ and Cl--Cl- distances 4.05 Å and 3.75 Å, respectively. The ratio of the anion-anion pair distance to the cation-anion pair distance (r--/r+-) was, therefore, 1.43, being close to 1.41, characteristic of octahedral geometry. These results indicate that ErCl63--octahedra exist in molten ErCl3. Probably Er2Clio and a small amount of Er2Cl115- ions are formed according to the geometrical calculations of bond lengths and bond angles.

Electrical conductivity of molten YCl3NaCl, YCl3KCl and YCl3CaCl2 systems

Abstract Electrical conductivities κ of molten YCl 3 NaCl, YCl 3 KCl, and YCl 3 CaCl 2 systems were measured, from which equivalent conductivities Λ were evaluated using the molar volume data.

Polarization phenomenon in molten MgCl2-KCl and MgCl2-NaCl

Abstract Refractive indices of molten binary MgCl2-NaCl and MgCl2-KCl mixtures have been measured by the goniometer method with visible light at nine wa

X-ray diffraction study of molten eutectic LiF–NaF–KF mixture

The structure of molten eutectic LiF–NaF–KF (46.5; 11.5; 42.0 mol%) mixture at 520 °C has been investigated using the radial-distribution function based on X-ray scattered intensity data and analysed by the correlation method. The nearest-neighbour distances of unlike-ions, Li–F, Na–F and K–F, were 1.83, 2.18 and 2.59 A, respectively, and their respective coordination numbers were 3.3, 3.8 and 4.0. These values are almost the same as those in the pure melts. The result indicates that in the ternary mixture the short-range structures of unlike ion pairs do not change on mixing nor in binary melts.