Polychalcogenophosphate flux synthesis of 1D-KInP₂Se₆ and 1D and 3D-NaCrP₂S₆

Three new chalcogenophosphates, 1D-KInP₂Se₆ (I), 1D-NaCrP₂S₆ (II) and 3D-NaCrP₂S₆ (III), have been synthesized and their structure determined from single crystal diffraction analysis. (I) and (II) crystallize in the monoclinic system (space group P2₁/n, No. 14) with cell parameters a = 7.5112(11), b = 6.4861(5), c = 22.789(2) Å and β = 98.912(16)° (V = 1096.9(2) ų), Z = 4 and R/Rw(F²) = 0.0234/0.0387 (for 900 observed reflections and 92 refined parameters) for (I) and a = 7.0279(5), b = 5.8797(2), c = 21.2578(14) Å and β = 92.110(3)° (V = 877.82(9) ų), Z = 4 and R/Rw(F²) = 0.0572/0.1151 (for 1455 observed reflections and 92 refined parameters) for (II). Both materials exhibit/∞[MP₂Q₆]^- chains built upon [MQ₆] octahedra (M = In, Cr; Q = Se, S) sharing edges to define/∞[MQ₄]^5- zigzag fibers which are capped by tetradentate ethane-like [P₂Q₆] groups. (III) crystallizes in the orthorhombic system (space group Fdd2, No. 43) with cell parameters a = 10.9742(7), b = 7.9828(6), c = 20.8590(19) Å (V = 1827.3(4) ų), Z = 8 and R/Rw = 0.0184/0.0378 (for 967 observed reflections and 47 refined parameters), and displays a three-dimensional framework arrangement. Its structure is similar to that of TiP₂S₆ where titanium atoms are substituted for the chromium, the sodium atoms being inserted in the empty tunnels to ensure the charge balance. The exfoliation properties of 1D-NaCrP₂S₆ in polar solvents are reported.