A novel two-dimensional mercury antimony telluride: low temperature synthesis and characterization of RbHgSbTe3

RbHgSbTe3 (I), a novel two-dimensional quaternary mercury antimony telluride, was synthesized via an unconventional low-temperature route. Single crystals of I were grown at 180 degrees C from solvothermal reactions using ethylenediamine as solvent. The crystal structure of I was determined by X-ray diffraction methods. The structure belongs to the orthorhombic crystal system, space group Cmcm (no. 63), a = 4.590 (2) Angstrom, b = 15.745 (4) Angstrom, c = 11.737 (2) Angstrom, Z = 4. The crystal structure of this compound consists of two-dimensional layers of (2)(infinity)[HgSbTe3-] with Rb+ counterions located between the layers. Optical studies performed on the powder samples of I suggested that the compound is a narrow-gap semiconductor. A band-gap of 0.2 eV was estimated from its diffuse reflectance spectrum.