Temperature controlling valance changes of crystalline thioarsenates and thioantimonates

•Six thioarsenates and thioantimonates with different valences of As/Sb were synthesized by adjusting the temperature.•Cs2Ag6As2S7 (5) exhibits the highest Ag/As ratio among the known quaternary sulfides.•Compounds 4 and 5 exhibit excellent photoelectric responsive properties. [Display omitted] Six thioarsenates and thioantimonates with different valences of As/Sb were synthesized solvothermally by adjusting the synthetic temperature. Rb2AgAsS4 (1), Cs2AgAsS4 (2), Cs2AgSbS4 (3) in which As and Sb are pentavalent were obtained in the lower temperature system and RbAg2AsS3 (4), Cs2Ag6As2S7 (5), and CsAg2SbS3 (6) in which As and Sb are trivalent were synthesized under a higher temperature. Compounds 1–3 possess the same one-dimensional (1D) chain structure and 4–6 are two-dimensional (2D) layered compounds. In particular, 5 exhibits the highest Ag/As ratio (3.0) among the known quaternary sulfides, and rare octahedral coordinated S2- ions that coordinate with six Ag+ ions exist in the structure of it. Their optical properties, photoelectric response properties, and theoretical calculations have also been studied.