Crystallographic and Thermal Properties

IR and Raman spectra of crystalline OFg indicate that OFg is not centrosymmetric. It contains at least two molecules per unit cell of Cg or C symmetry [1]. 

Pycnometric measurements of liquid OFg between -195.70 and -148.52°C resulted in the following (selected) values represented by q = 0.8225-0.0048731 [4]  

Measurements of liquid OFg (by the flotation-temperature method) in a narrow range near its boiling point gave the following values [5]  

Vapor Pressure p. Boiling Point tj. Heat of Vaporization AH  

Measured vapor pressures (selected values) for essentially 100% pure OF2 [7] follow  

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STUDIES ON CLATHRASILS VII. A NEW CLATHRATE COMPOUND OF SILICA SYNTHESIS, CRYSTALLOGRAPHIC, AND THERMAL PROPERTIES. 

H. GIES / Synthesis, Crystallographic, and Thermal Properties of a New Porous Silica 283... 

Gies, H. - Synthesis, crystallographic and thermal properties of a new porous silica... 

Some X-ray density data are given in the Section 4.1.3.2 Crystallographic and Structural Properties (see pp. 15/7). The thermal expansion is determined only by X-ray diffraction from the change in the lattice parameter for details see p. 17. 

Many of the properties of ceria are intimately related to the tolerance of the fluorite structure towards high concentrations of oxide ion vacancies. In order to select the most appropriate doped ceria composition for a specific application, it is necessary to know the defect chemistry and thermochemistry of doped ceria and its relation to the thermomechanical, crystallographic, and transport properties. A brief description of the defect chemistry of ceria is provided in Section 12.2 of this chapter, followed by a short presentation of its thermal, crystallographic, and chemical properties and their dependence on doping and reduction. Thermodynamic data on X (in CeOg- ) as a function of oxygen partial pressure pOg and temperature, as well as the effect of substituents and particle size, will be a central topic of this chapter and will be discussed in Section 12.3. 

It exhibits anisotropic physical properties as a result of its crystallographic structure of well-separated parallel sheets of carbon atoms. Thus graphite single cry.stals exhibit far higher electrical and thermal conductivity parallel to the layers of carbon atoms than perpendicular to them. Macroscopically, however, this anisotropy is seldom observable due to the random orientation of the individual particles. 

Stern, K. H., High Temperature Properties and Thermal Decomposition of Inorganic Salts with Oxyanions, CRC Press, Boca Raton, FL, 2001. Donnay, J.D.H., and Ondik, H.M., Crystal Data Determinative Tables, Third Edition, Volumes 2 and 4, Inorganic Compounds, Joint Committee on Powder Diffraction Standards, Swarthmore, PA, 1973. Robie, R., Bethke, P. M., and Beardsley, K. M., Selected X-ray Crystallographic Data, Molar Volumes, and Densities of Minerals and Related Substances, U.S. Geological Survey Bulletin 1248,1967. Carmichael, R. S., Practical Handbook of Physical Properties of Rocks and Minerals, CRC Press, Boca Raton, FL, 1989. 

Some magnetic properties of the Sm, Nd, and Pr monoxides obtained at high pressures and temperatures, have been also reported [37]. From the thermal change of the magnetic susceptibilities and the lattice constants for both NdO and PrO, a trivalency of their metal atom state is identified. On the other hand, Sm ion in SmO seems to hold a nearly trivalent state from the crystallographic and X-ray absorption data. 

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