화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.244, 313-318, 1994
Low-Temperature Structures of Stage-2 Cesium Graphitides with Various Compositions
Compounds with the compositions CsC22, CsC24, and CsC28 were synthesized from H.O.P.G platelets and characterized by X-ray diffraction. All the specimens are basically 2nd stage phases. CsC24 appears as an almost pure phase, whereas CsC22 and CsC28 contain respectively a trace of 1st stage CsC8, and a relatively large amount of 3rd stage phase. Fourier analysis of the 00l reflexions shows that the composition range for the 2nd stage compound seems to be very limited, and close to CsC24. From the 00l scans realized in the range 300 K-77 K, a first order transition was observed for the 2nd stage phase at about 155 K, giving two new 2nd stage phases, respectively with Ic=9.33 Angstrom (main phase), and Ic=9.58 Angstrom. This transition is attributed to the freezing of the cesium film leading to a 2D segregation inside a unique grain. The domains could be separated by pleats distributed along a canted front.