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Abstract: Lanthanide trichlorides which hardly react with graphite have been moved into the latter by chemical vapor transport (CVT) thanks to a gaseous complex LnAl3Cl12 resulting from the reaction between LnCl3 and AlCl3. This complex molecule also allows the intercalation of LnCl3 into graphite, AlCl3 playing the role of a gaseous medium and/or co-intercalated species, depending on the structure of the pristine chloride. Well-defined stage-2 to 4 graphite intercalation compounds (GICs) have been synthesized by this CVT method, but efforts to get richer stage-1 compounds are still in progress. The 00 l structural study of stage-2 GICs performed by XRD reveals that interplanar distances of LnCl3-GICs are higher than those classically observed for intercalated transition metal chlorides. The composition of all the stage-2 compounds studied has been established and ternary C-LnCl3–AlCl3 compounds with a significant excess of chlorine have been observed. The 2D structures of the different LnCl3-GICs have been characterized by X-ray or electron diffraction and show that structural differences are noted between pristine and intercalated LnCl3. [Copyright &y& Elsevier]

Abstract: The formation of the vapor complex DyAl3Cl12 by action of gaseous Al2Cl6 on dysprosium chloride has been performed to synthesize a stage-2 DyCl3‐Graphite Intercalation Compound (GIC). EDS experiments prove that no AlCl3 is co-intercalated and 00l X-rays analysis leads to the chemical formula C17.36DyCl3.66. The c-axis repeat distance I C=1314±5pm and the stacking sequence of intercalated DyCl3 along the c-axis corresponds to the layer sandwich Cl–Dy–Cl where the distance between Dy and Cl layers is 149pm. The DyCl3 in-plane structure is oblique with lattice parameters a=1486pm, b=1746pm, γ=66.3°. It presents two different micro-domains disorientated from graphite lattice by θ 1=±9°. Free and intercalated DyCl3 present paramagnetic behaviour following Curie–Weiss law. [Copyright &y& Elsevier]

Abstract: A stage-2 HoCl3-GIC has been synthesized and characterized by XRD experiments and magnetic measurements. EDS and 00l X-ray analyses lead to the chemical formula C23.8HoCl3.7.The c-axis repeat distance is 1313±5pm, and the stacking sequence of intercalated HoCl3 along the c-axis corresponds to the layer sandwich Cl–Ho–Cl, where the distance between Ho and Cl layers is 157pm. The HoCl3 in-plane structure is oblique with lattice parameters a =689pm, b =1177pm, γ =149.6° close to those in the pristine crystal. It presents two different micro-domains disorientated with respect to graphene planes by θ 1 =±19°. Magnetic studies show that Ho3+ ions obey the Curie–Weiss law for both pristine HoCl3 and stage-2 HoCl3-GIC. The presence of graphene planes between HoCl3 intercalated layers leads to an increased Curie–Weiss temperature and to a decrease in the weak antiferromagnetic interactions between Ho3+ ions. [Copyright &y& Elsevier]

In this work, we present a chemical vapor transport process involving the gaseous species DyAl 3 Cl 12 (g) in order to perform the intercalation of dysprosium trichloride into graphite. Even if it is known that such a reaction must be performed under chlorine atmosphere, this work reveals that an increase of the Cl 2 pressure in the synthesis reactor improves the intercalation yield. By combination of gravimetric measurement, EDX analysis and 00 l X-ray diffraction experiments, we evidence the synthesis of a novel 1st stage DyCl 3 -Graphite Intercalation Compound (GIC). The sample obtained in this study is a mixture of 1st stage DyCl 3 -GIC and 2nd stage AlCl 3 -GIC. However, considering the 1st stage DyCl 3 -GIC, the data collected in this work are in agreement with a I C repeat distance of 982 pm and a C 8.1 DyCl 3.9 formula. Along the c -axis, the intercalated sheet is three-layered and exhibits a Cl-Dy-Cl stacking sequence existing in pristine chloride. [Display omitted] • Chemical vapor transport is used for intercalation reaction (topotactic reactions). • A novel 1st stage DyCl 3 - graphite intercalation compound is obtained. • The intercalated sheet is a three-layered sandwich existing in pristine DyCl 3. [ABSTRACT FROM AUTHOR]