Crystal structure of the ammoniated alkali fulleride, (NH3)K3C60, was studied by high resolution x-ray diffraction experiments. We found a structural phase transition at low temperature. A superstructure appears below the transition temperature, Ts ≅ 150 K, and it originates from the orientational ordering of K-NH3 pairs in the octahedral site. Below Ts, K-NH3 pairs align in an antiferroelectric fashion, which is understood by electrostatic interaction between them. We also measured a deuteration effect to the transition. Similar transition was observed in (ND3)K3C60 and difference in Ts was very little.
|Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals
|Published - 2000
ASJC Scopus subject areas