Pressure and temperature dependences of the structural properties ofDy@C82isomer I

Crystals of $\mathrm{Dy}@{\mathrm{C}}_{82}$ isomer I are studied by x-ray powder diffraction with synchrotron radiation in wide temperature and pressure regions. The isomer I of $\mathrm{Dy}@{\mathrm{C}}_{82}$ shows a simple cubic structure with lattice constant a of 15.85(3) Å at 298 K, while the isomer II shows a face-centered cubic structure with a of 15.75(4) Å. The structural phase transition of the second order is indicated for the isomer I at 300–310 K by the temperature dependence of x-ray diffraction and differential scanning calorimetry. Further, the pressure dependence of the lattice constant is studied for the isomer I up to 60 kbar, which can be fitted by a Murnaghan equation of state.