Single crystals of ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{CeNb}}_2$${\mathrm{S}}_5$ (x≊0.6) are grown by chemical-vapor-transport reaction of powder mixture of Cu and ${\mathrm{CeNb}}_2$${\mathrm{S}}_5$. The compound is regarded as a Cu intercalation derivative of a second-stage misfit-layer compound with incommensurate planar intergrowth structure of CeS and ${\mathrm{Cu}}_{\mathit{x}}$(${\mathrm{NbS}}_2$${)}_2$ layers. Two sublattices for CeS and ${\mathrm{Cu}}_{\mathrm{x}}$(${\mathrm{NbS}}_2$${)}_2$ layers have a different geometry in the a-b plane although the stacking direction coincides with the c axis. Lattice parameters are ${\mathit{a}}_1$=5.80 Å, ${\mathit{b}}_1$=5.80 Å, and ${\mathit{c}}_1$=17.93 Å for CeS layers and ${\mathit{a}}_2$=3.35 Å and ${\mathit{c}}_2$=1.93 Å for ${\mathrm{Cu}}_{\mathit{x}}$(${\mathrm{NbS}}_2$${)}_2$ layers, where ${\mathit{a}}_1$=√3${\mathit{a}}_2$. The composite crystals, which are represented by [${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{CeNb}}_2$${\mathrm{S}}_5$${]}_{\mathit{z}}$[${\mathrm{Cu}}_{\mathit{y}}$${\mathrm{NbS}}_2$${]}_{1\mathrm{-}\mathit{z}}$, [${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{SmNb}}_2$${\mathrm{S}}_5$${]}_{\mathit{z}}$[${\mathrm{Cu}}_{\mathit{y}}$${\mathrm{NbS}}_2$${]}_{1\mathrm{-}\mathit{z}}$, and [${\mathrm{SnNbS}}_3$${]}_{\mathit{z}}$[${\mathrm{Cu}}_{\mathit{y}}$${\mathrm{NbS}}_2$${]}_{1\mathrm{-}\mathit{z}}$, are also grown by a similar method. The single and the composite crystals are, respectively, formed by regular and irregular stacking of Cu and MS (M=Ce, Sm, and Sn) layers. The electronic structures are studied by means of x-ray photoemission spectroscopy and inner-shell-electron energy-loss spectroscopy methods. © 1996 The American Physical Society.

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