Gd2O3: Synthesis and X-Ray Diffraction Analysis of Single Crystals, Thermal Expansion in the Range of 90-490 K

A fine crystalline sample of the cubic modification (space group Ia (3) over bar, Z = 16) of gadolinium oxide (C-Gd O-2(3)) is grown by the solution-melt technique. The single crystal X-ray diffraction analysis performed at 150 K and 298 K reveals a relative increase in the unit cell parameter by 0.08%. The parameter at 300 K is refined by two independent procedures: in Bond's scheme (a = 10.8152(9) angstrom, relative error Delta a/a = 8 center dot 10(-5)) and by calibrating the equatorial circumference according to the external reference ( a = 10.8145(6) A, relative error Delta a/a = 5.1 center dot 10(-5)). The values obtained coincide within the experimental error with data for the polycrystalline reference described by the National Bureau of Standards of the United States. The dependence a(T) is studied in the range of 90-490 K with a step of 10 K. Experimental points are described by second degree polynomial a = 10.801 + 2.7 center dot 10(-5)T + 6.0 center dot 10(-8)T(2).