New Quaternary Thiostannates and Thiogermanates A₂Hg₃M₂S₈ (A = Cs, Rb; M = Sn, Ge) through Molten A₂S_x. Reversible Glass Formation in Cs₂Hg₃M₂S₈

Abstract

8 : a ) 7.878(2) Å, b ) 9.157(3) Å, c ) 6.803(2) Å, R ) 92.96(2)°, β ) 109.45(2)°, γ ) 107.81(2)°, V ) 434.1(2) Å 3 , and D calc ) 5.207 g/cm 3 . The unit cell of isostructural Cs 2 Hg 3 Ge 2 S 8 is a ) 7.808(2) Å, b ) 9.164(2) Å, c ) 6.612(2) Å, R ) 92.02(2)°, β ) 108.65(2)°g, γ ) 108.10(2)°, and V ) 419.9(2) Å 3 . Rb 2 -Hg 3 M 2 S 8 crystallize in the monoclinic space group P2 1 /c, Rb 2 Hg 3 Sn 2 S 8 : a ) 10.132(2) Å, b ) 6.540(2) Å, c ) 13.434(2) Å, β ) 97.93(1)°, V ) 881.7(6) Å 3 , and D calc ) 4.770 g/cm 3 . The unit cell of isostructural Rb 2 Hg 3 Ge 2 S 8 is a ) 9.938 (3) Å, b ) 6.352 (2) Å, c ) 13.117 (3) Å, β ) 97.33 (2)°, and V ) 821.3 (4) Å 3 . The structure of Cs 2 Hg 3 M 2 S 8 consists of [Hg 3 M 2 S 8 ] 2layers separated by Cs + cations. The layers contain tetrahedral Sn 4+ or Ge 4+ centers and two types of Hg 2+ , two coordinate linear and three-coordinate pseudotrigonal centers. The structure of Rb 2 Hg 3 M 2 S 8 consists of a 3-dimensional [Hg 3 M 2 S 8 ] 2framework with Rb + cations located within channels of the structure. This structure also contains tetrahedral Sn 4+ or Ge 4+ centers and two types of Hg 2+ , the two-coordinate linear type and a four-coordinate "seesaw" geometry. Optical band gaps, determined from single-crystal UV/vis spectroscopy, range from 2.52 eV in the tin-based compounds to 2.89 eV in the germanium-based analogues. Cs 2 Hg 3 M 2 S 8 become glasses upon melting. Infrared and Raman spectroscopic characterization of the glasses are reported.

Heterostructured Visible‐Light‐Active Photocatalyst of Chromia‐Nanoparticle‐Layered Titanate

“…The bandgap energy (E g ) was evaluated by the linear interpolation of a/S absorption coefficients converted from the reflectance data through the Kubelka-Munk function. [22] The pristine cesium titanate is a wide bandgap semiconductor with E g = 3.5 eV. Upon hybridizing with visible absorbing chromia species, an absorption edge shifts to a lower energy region of 2.2-2.4 eV.…”

Solid-state syntheses, crystal structures and properties of two novel metal sulfur chlorides—Zn6S5Cl2 and Hg3ZnS2Cl4

“…The transition metal and main group metal chalcogenides show rich structural chemistry and useful physical and chemical properties for potential applications in nonlinear optics [1][2][3][4], optical storage [5][6][7][8][9], solar energy conversion [10,11], thermal electrics [12][13][14][15][16], ion-exchange [17,18], second harmonic generation [19], chemical absorption [20][21][22][23], ferroelectrics [24] and so forth. Nowadays, many metal chalcogenides have been synthesized and some of them have been widely used in military and civil areas, famous examples including CuInSe 2 and Hg 1À x Cd x Te, whose primary applications are found in photovoltaic devices for solar energy conversion and infrared detection [10,11,25].…”

(NH3CH2CH2NH3)Ag2SnS4: a quaternary sulfide-containing chiral layers

“…Up to now most known quaternary chalcogenides were prepared using the molten alkali-metal polychalcogenide flux and high-temperature solid state techniques [6,7]. Quaternary chalcogenides may exhibit interesting properties due to a variety of compositions and structures, therefore syntheses of new quaternary chalcogenides are becoming an active area of solid state chemistry [3].…”