The solvothermal synthesis and characterization of quaternary arsenic chalcogenides CsTMAsQ3 (TM = Hg, Cd; Q = S, Se) using Cs+ as a structure directing agent: from 1D anionic chains to 2D anionic layers

Abstract

Four new quaternary transition metal arsenic chalcogenide Cs-TM-As-Q compounds (TM = Hg, Cd; Q = S, Se) were synthesized using different mixed solvents. A 1,4-diaminobutane(1,4-dab)/water mixed solvent system was used to solvothermally synthesize the selenoarsenates CsTMAsSe₃ (TM = Hg (1), Cd (2)). In 1, the eight-membered ring anion chain consists of trigonal-planar [HgSe₃] and trigonal-pyramid [AsSe₃]. Compound 2 is similar to the eight-membered ring chain anion of compound 1, and [CdAsSe₃]^- further joins, through μ₃-Se and Cd, to form the layer anions [CdAsSe₃]^-. A 2-diaminopropane (1,2-dap) and water mixed solvent system was used to synthesize two thioarsenates, Cs₂TM₂As₂S₆ (TM = Cd (3), Hg (4)). Compounds 3, 4 and 2 are isostructural; the Cd and Hg atoms are four coordinated. Compounds 1-4 utilize Cs⁺ cations as a structural directing agent. Finally, the structural and optical properties of the novel series of arsenic chalcogenides were characterized.