Cubic phase transition temperature

As shown before, using/ /os = 0 and dfcjos/3 2 (2) = 0, gives the reduced isotropic-cubic phase transition temperature ... 

Abstract. Gas interstitial fullerenes was produced by precipitation of C6o from the solution in 1,2 dichlorobenzene saturated by O2, N2, or Ar. The structure and chemical composition of the fullerenes was characterized by X-ray powder diffraction analysis, FTIR spectroscopy, thermal desorption mass spectrometry, differential scanning calorimetric and chemical analysis. The images of fullerene microcrystals were analyzed by SEM equipped with energy dispersive X-ray spectroscopy (EDS) attachment. Thermal desorption mass spectroscopy and EDS analysis confirmed the presence of Ar, N and O in C60 specimens. From the diffraction data it has been shown that fullerite with face centered cubic lattice was formed as a result of precipitation. The lattice parameter a was found to enhance for precipitated fullerene microcrystals (a = 14.19 -14.25 A) in comparison with that for pure C60 (a = 14.15 A) due to the occupation of octahedral interstices by nitrogen, oxygen or argon molecules. The phase transition temperature and enthalpy of transition for the precipitated fullerene microcrystals decreased in comparison with pure Cgo- Low temperature wet procedure described in the paper opens a new possibility to incorporate chemically active molecules like oxygen to the fullerene microcrystals. 

Fig. 89. Magnetic data for the mixed system (Zni Ax)CMns, where A Al, Ga, Mn. (a) Variation of Bohr magnetons per Mn atom with composition. (Ordinary values obtained b r extrapolation from cubic phase extraordinary value corresponds to low-temperature tetragonal phase.) (b) (facing page) Variation of Curie and phase-transition temperatures with composition. (After Howe and Myers (282).)...

Fig. 2 a Plot of lattice parameter of Cs2NaLnX6 (X=C1, Br, F) against 6-coordinate ionic radius of Ln3+ (data from [8]). b Plot of cubic to tetragonal phase transition temperature, Tc, against lattice parameter extrapolated to Tc (data from [8, 37, 41, 43, 50, 60]). The linear regressions in b are shown as a guide to the eye... 

Zirconium dioxide, zirconia, is the only oxide of zirconium stable chemically at temperatures below 2000 K. At higher temperatures some dissociation into ZrO and oxygen takes place. The phases of ZrOj, their densities, and phase-transition temperatures are listed in Table 7.5. Zirconia stabilized in the high-temperature cubic phase by addition of 3 to S percent calcium oxide is used as a refractory at temperatures up to 2200° C. ZrOj has been used to dilute UOj in fuel elements. 

The cubic to tetragonal phase-transition temperatures of all the lanthanide dicarbides (Table 7), with the exception of SmCg, TbCg, and TmCg, have been... 

It has been reported that Y2O3 nanoparticles as-prepared by gas phase synthesis have the monoclinic stmcture of high pressure phase, which transforms into cubic Y2O3 above 873 K [7,8]. It has been elucidated from the dependence of the phase transition temperature on the state of compaction that the stability of the high pressure phase is due to the nanostructured particle size. 

Beister. H.J., StrOssner, K. Syassen, K. (1990). Rhomboedral to simple-cubic phase transition in arsenic under pressure. Phys. Rev. B, 41,5535-5543 Chapuis, G. Zufiiga, F. (1988). The High temperature Phase of (CH3)3NHCdCl3 or How to Minimize Order-Disorder Effects in Phase Transitions. Acta Cryst. B44,243-249. International Tables for X-ray Crystallography (1983). Dordrecht Reidel. 

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