Structure and synthesis of the ternary alkali graphite intercalation compound KCsC16, an ideal layered heterostructure

• Published in: The Journal of chemical physics 1985-01, Vol.82 (2), p.921-926
• Main Authors: HARK, S. K, YORK, B. R, SOLIN, S. A
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic compounds; Miscellaneous; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.448522

We have prepared a stable two phase graphite intercalation compound (GIC) containing KC8 and KCsC16 by immersing CsC24 into liquid K at 70 °C. High resolution x-ray diffraction studies reveal that the KCsC16, which exhibits a stage one c-axis stacking sequence of ⋅⋅⋅ C K C Cs C K C Cs ⋅⋅⋅ is an ideal ternary heterostructure GIC with a c-axis repeat distance of dH=11.27 Å and correlation range of 350 Å. The intensities of the (00l) x-ray diffraction pattern calculated on the basis of the proposed c-axis repeat sequence are in excellent agreement with the experimental observations. The KCsC16 in plane structure is a (2×2)R0 ° superlattice with an in plane correlation range of 140 Å. The ordered intercalant layers stack along the c axis with an α,β,γ,δ site sequence, where, e.g., α,γ=K and β,δ=Cs, and stacking faults occur on average every 30 Å.