Incorporation of A₂Q into HgQ and Dimensional Reduction to A₂Hg₃Q₄ and A₂Hg₆Q₇ (A = K, Rb, Cs; Q = S, Se). Access of Li Ions in A₂Hg₆Q₇ through Topotactic Ion-Exchange

Abstract

The synthesis of the one-dimensional K2Hg3Q4 (Q = S, Se) and Cs2Hg3Se4 and the three-dimensional A2Hg6S7 (A = K, Rb, Cs), and A2Hg6Se7 (A = Rb, Cs) in reactive A2Q x fluxes is reported. Pale yellow, hexagonal plates of K2Hg3S4 crystallize in space group Pbcn, with a = 10.561(5) Å, b = 6.534(3) Å, and c = 13.706(2) Å, V = 945.8(7) Å, d calc = 5.68 g/cm3, and final R = 5.7%, R w = 6.3%. Red, hexagonal plates of K2Hg3Se4 crystallize in space group Pbcn, with a = 10.820(2) Å, b = 6.783(1) Å, and c = 14.042(2) Å, V = 1030.6(5) Å, d calc = 6.42 g/cm3, and final R = 7.7%, R w = 8.4%. Orange yellow, hexagonal plates of Cs2Hg3Se4 crystallize in space group Pbcn, with a = 12.047(4) Å, b = 6.465(2) Å, and c = 14.771(6) Å, V = 1150.4(7) Å, d calc = 6.83 g/cm3, and final R = 5.5%, R w = 6.2%. Black needles of K2Hg6S7 crystallize in space group P4̄21 m, with a = 13.805(8) Å and c = 4.080(3) Å, V = 778(1) Å, d calc = 6.43 g/cm3, and final R = 3.1%, R w = 3.6%. Black needles of Rb2Hg6S7 crystallize in space group P42 nm, with a = 13.9221(8) Å and c = 4.1204(2) Å, V = 798.6(1) Å, d calc = 6.65 g/cm3, and final R = 4.3%, R w = 5.0%. Black needles of Cs2Hg6S7 crystallize in space group P42 nm, with a = 13.958(4) Å and c = 4.159(2) Å, V = 810.2(8) Å, d calc = 6.94 g/cm3, and final R = 4.3%, R w = 4.4%. Black needles of Cs2Hg6Se7 crystallize in space group P42 nm, with a = 14.505(7) Å and c = 4.308(2) Å, V = 906(1) Å, d calc = 7.41 g/cm3, and final R = 3.6%, R w = 4.0%. The A2Hg3Q4 compounds contain linear chains. The A2Hg6Q7 compounds display noncentrosymmetric frameworks with A+ cations residing in tunnels formed by both tetrahedral and linear Hg atoms. K2Hg6S7, Rb2Hg6S7, Cs2Hg6S7, Rb2Hg6Se7, and Cs2Hg6Se7 display room-temperature bandgaps of 1.51, 1.55, 1.61, 1.13, and 1.17 eV, respectively. Bandgap engineering through S/Se solid solutions of the type Rb2Hg6Se7 - x S x and Cs2Hg6Se7 - x S x is possible in these materials. All A2Hg6Q7 melt congruently, with melting points of 556 ± 10 °C, except for Rb2Hg6Se7 which degrades. Rb2Hg6S7 can undergo ion exchange reactions with LiI to give Li1.8Rb0.2Hg6S7.

Synthesis, structure and properties of (4,4′-H2bipy)[HgBr4]·H2O with strong fluorescence

“…3), which suggests that compound 1 shows a semiconductor property and is consistent with the yellow color of the crystal, as the case found in the reference [14]. The gradual slope of the optical absorption edge for 1 is indicative of the existence of indirect transitions [15].…”

Synthesis, crystal structure and properties of [Er(C6H5NO2)3(H2O)2]n(1.5nZnCl4)·(2nH2O) with strong luminescence

“…Packing diagram of 1 with the dashed lines representing hydrogen bonds (Å): O1WÁÁÁCl1(1/2 À x, À1/2 + y, 1/2 À z) 3.205 (2), O2WÁÁÁCl2(x, Ày, À1/2 + z) 3.228 (1), O2WÁÁÁO4W 2.731(2), O3WÁÁÁCl4(1/2 À x, À1/2 À y, 1 À z) 3.240 (2), O3WÁÁÁO3W(1 À x, y, 3/2 À z) 2.984 (3), O3WÁÁÁN3 2.857(4), O4WÁÁÁCl3(x, y, À1 + z) 3.249 (3), O4WÁÁÁCl4(x, Ày, À1/2 + z) 3.224 (2) Optical absorption spectrum of 1 reveals the presence of an obviously optical gap of 3.85 eV (Fig. 5), which suggests that complex 1 may be a potential wide-gap semiconductor and is consistent with the color of the crystal, as the cases found in the reference [9]. The steep slope of the optical absorption edge for 1 is indicative of the existence of direct transitions [10].…”

Bismuth Iodide Hybrid Organic‐Inorganic Crystal Structures and Utilization in Formation of Textured BiI3 Film

“…1D K 2 Hg 3 S 4 . [18] The use of single BiI 3 chains still needs to be investigated. Hence, the infinite linear chain 1 ∞ [BiI 3 ] has not previously been observed and might fertilize new technological applications of heavy metal iodides.…”