Quaternary Mercury Research Articles

Mercury Bismuth Chalcohalides, Hg3Q2Bi2Cl8 (Q = S, Se, Te): Syntheses, Crystal Structures, Band Structures, and Optical Properties

Three quaternary mercury bismuth chalcohalides, Hg3Q2Bi2Cl8 (Q = S, Se, Te), are reported along with their syntheses, crystal structures, electronic band structures, and optical properties. The compounds are structurally similar with a layer comprised of a hole perforated sheet network of [Hg3Q2](2+) (Q = S and Te) that forms by fused cyclohexane, chairlike Hg6Q6 rings. The cationic charge in the network is balanced by edge-sharing monocapped trigonal-prismatic anions of [Bi2Cl8](2-) that form a two-dimensional network located between layers. Compound 1, Hg3S2Bi2Cl8, crystallizes in the monoclinic space group C12/m1 with a = 12.9381(9) Å, b = 7.3828(6) Å, c = 9.2606(6) Å, and β = 116.641(5)°. Compound 2, Hg3Te2Bi2Cl8, crystallizes in the monoclinic space group C12/c1 with a = 17.483(4) Å, b = 7.684(2) Å, c = 13.415(3) Å, and β = 104.72(3)°. The crystals of the Hg3Se2Bi2Cl8 analogue exhibit complex modulations and structural disorder, which complicated its structural refinement. Compounds 1 and 2 melt incongruently and show band gaps of 3.26 and 2.80 eV, respectively, which are in a good agreement with those from band-structure density functional theory calculations.

Synthesis, crystal and band structures, and optical properties of a novel quaternary mercury and cadmium chalcogenidehalide: (Hg2Cd2S2Br)Br

A novel quaternary mercury and cadmium chalcogenidehalide, (Hg2Cd2S2Br)Br (1), has been prepared by solid-state reaction and structurally characterized by single crystal X-ray diffraction analysis. The structure of 1 is composed of parallel slabs stacking with -ABAB- mode via linearly coordinated Hg atoms to form a 3D cationic network with the channels being occupied by discrete Br anions, in which the slab consists of interlinks of linear (HgS2Br2) tetrahedral chains and (CdS2Br) trigonal chains. The optical properties were investigated in terms of the diffuse reflectance and Fourier transform infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is a semiconductor with an indirect band gap, and that the optical absorption is mainly originated from the charge transitions from Br-4p and S-3p to Cd-5s and Hg-6s states.

Synthesis, Crystal and Band Structures, and Properties of a New Mixed Three‐Dimensional Framework Metal Pnictidehalide Semiconductor, (Hg6Sb4)(CdI6).

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Synthesis, Crystal and Band Structures, and Properties of a New Mixed Three-Dimensional Framework Metal Pnictidehalide Semiconductor, (Hg6Sb4)(CdI6)

A new, quaternary mercury and cadmium pnictidehalide semiconductor (Hg6Sb4)(CdI6) (1) has been prepared by the solid-state reaction and structurally characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in the space group R-3c of the rhombohedral system with four formula units in a cell: a=13.3818(9) A, alpha=90.93 degrees, and V=2395.3(3) A3. The crystal structural novelty of 1 derives from the fact that a 3-D mercury antimonide cationic network interpenetrates with an unusual 3-D cadmium iodide octahedral anionic network through the weak covalent interactions between mercury and iodine atoms to form a mixed 3-D framework. Among them, the cationic moiety features a perovskite-like 3-D network while the anionic moiety is characterized by a 3-D I6 octahedral anionic network with two-thirds I6 octahedra being occupied by Cd atoms. The optical properties were investigated in terms of the diffuse reflectance and Fourier transform infrared spectra. The electronic band structure along with density of states calculated by the density functional theory method indicates that compound 1 is a semiconductor with a direct band gap and that the optical absorption of 1 is mainly ascribed to the charge transitions from I-5p and Sb-5p states to Cd-5s and Hg-6s states.

New Quaternary Selenoantimonates AHgSbSe3 (A = Rb, Cs): Synthesis, Structures and Optical Properties

AbstractSolvothermal reactions in ethylenediamine have resulted in two quaternary mercury containing selenoantimonates: RbHgSbSe3 (I) and CsHgSbSe3 (II). Compound I crystallizes in monoclinic system, space group P2l/c (no. 14) with a = 7.758(2)Å, b = 11.234(2)Å, c = 8.849(2) Å, β = 106.60(3)°, V = 739.1(3)Å3, Z = 4. Compound II crystallizes in orthorhombic system, space group Cmcm (no. 63) with a = 4.444(1)Å, b = 15.514(6)Å, c = 11.261(7) Å, V = 776.4(6) Å3, Z = 4. Both compounds are layered materials and their crystal structures are closely related. Both contain layers of 2[HgSbSe3-] separated by alkali-metal cations A+ (Rb, Cs). Diffuse reflectance experiments show that both compounds are semiconductors with estimated band gaps of 1.7 eV for I and 1.6 eV for II, respectively.

A novel two-dimensional mercury antimony telluride: low temperature synthesis and characterization of RbHgSbTe 3

RbHgSbTe 3 (I), a novel two-dimensional quaternary mercury antimony telluride, was synthesized via an unconventional low-temparature route, Single crystals of I were grown at 180°C from solvothermal reactions using ethylenediamine as solvent. The crystal structure of I was determined by X-ray diffraction methods. The structure belongs to the orthorhombic crystal system, space group Cmem (no. 63). a = 4,590 (2) Å, b = 15.745 (4) Å, c = 11.737 (2) Å, Z = 4. The crystal structure of this compound consists of two-dimensional layers of ∗ 2[HgSbTe 3 =] with Rb ∗ counterions located between the layers. Optical studies performed on the powder samples of I suggested that the compound is a narrow-gap semiconductor. A band-gap of 0.2 eV was estimated from its diffuse reflectance spectrum.