ABSTRACTIn α-C5n-HNO3 the condensation of the room-temperature liquid-like diffuse ring associated with the disorder-order transition around 250 K is studied and the low-temperature. superstructure is examined.It is found that β-C8n-HNO3 exhibits an in-plane incommensurate order at room temperature.Two types of graphite-Br2 are found. Low-temperature phase transitions in C8Br are observed at T1 ≍ 277 K and T2 ≍ 297 K. The room-temperature structure of C14Br is reexamined. Special attention is given to diffuse scattering and incommensurability.
AbstractThis paper deals with X-ray single crystal experiments of modulated cobalt åkermanite at temperatures between 30 K and 600 K. The primary objective of these investigations was to study the predicted lock-in phase transition into a commensurate low temperature phase. Upon cooling the phase transition occurs at 160 K, provided that the time for thermodynamic equilibration at each temperature step is guaranteed. The low temperature phase turns out to be incommensurate with a modulation wavelength of 3.086(6) ·
A single-crystal X-ray study on the low-temperature phase transitions in leonite-type compounds
