The crystal structure of covellite

Roberts, H. S.; Ksanda, C. J.

doi:10.2475/ajs.s5-17.102.489

Cited by 11 publications

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“…CuS at room temperature has a hexagonal crystal structure, for which we calculate bond lengths of 2.142 Å for S−S, 2.263 Å for Cu1−S*, 2.417 Å for Cu2−S*, and 2.372 Å for Cu2−S1(S2), in agreement with previously reported values (S−S=2.113 Å, Cu1−S*=2.208 Å, Cu2−S*=2.374 Å, and Cu2−S1(S2)=2.322 Å) [27] . The lattice parameters of the optimized CuS structure are a = b =3.919 Å and c =16.814 Å, also in good agreement with the experimental values ( a = b =3.972 Å, c =16.972 Å) [51,52] …”

Section: Resultssupporting

confidence: 90%

“…[27] The lattice parameters of the optimized CuS structure are a = b = 3.919 Å and c = 16.814 Å, also in good agreement with the experimental values (a = b = 3.972 Å, c = 16.972 Å). [51,52] The calculated electronic band structure and density of states (DOS) of CuS are shown in Figure 3. The band structure shows that the valence band (VB) maximum is above the Fermi level, meaning the valence band is partially unoccupied, consistent with previous work.…”

Section: Undoped Cusmentioning

confidence: 99%

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Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Oppong‐Antwi,

Huang,

Hart

2023

ChemPhysChem

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CuS is a unique semiconductor with potential in optoelectronics. Its unusual electronic structure, including a partially occupied valence band, and complex crystal structure with an S−S bond offer unique opportunities and potential applications. In this work, the use of doping to optimize the properties of CuS for various applications is investigated by density functional theory (DFT) calculations. Among the dopants studied, Ni, Zn, and Mg may be the most practical due to their lower formation energies. Doping with Fe, Ni, or Ca induces significant distortion, which may be beneficial for achieving materials with high surface areas and active states. Significantly, doping alters the conductor‐like behavior of CuS, opening a band gap by increasing bond ionicity and reducing the S−S bond covalency. Thus, doping CuS can tune the plasmonic properties and transform it from a conductor to an intrinsic fluorescent semiconductor. Ni and Fe doping give the lowest band gaps (0.35 eV and 0.39 eV, respectively), while Mg doping gives the highest (0.86 eV). Doping with Mg, Ca, and Zn may enhance electron mobility and charge separation. Most dopants increase the anisotropy of electron‐to‐hole mass ratios, enabling device design that exploits directional‐dependence for improved performance.

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Section: Resultssupporting

confidence: 90%

Section: Undoped Cusmentioning

confidence: 99%

Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Oppong‐Antwi,

Huang,

Hart

2023

ChemPhysChem

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“…Compound I was synthesized by reacting 58.3 mg (0.251 mmol) of Th, 129.3 mg (2.030 mmol) of Cu, 65.1 mg (2.03 mmol) of S, and 34.3 mg (0.241 mmol) of K 2 S 2 . Following washing by DMF, the sample contained a mixture of colorless rod/plate crystals of I , the metallic green ternary KCu 4 S 3 , and the metallic purple covellite phase of the mineral CuS (both identified by single-crystal cell parameters). , Compound I was the minor component of the mixture, at approximately 25% of the bulk. EDS analysis of selected single crystals of I revealed the following composition normalized to Th: K 0.833 Cu 1.05 ThS 2.37 .…”

Section: Methodsmentioning

confidence: 99%

Three New Phases in the K/Cu/Th/S System: KCuThS₃, K₂Cu₂ThS₄, and K₃Cu₃Th₂S₇

et al. 2005

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Synthetic exploration of K/Cu/Th/S quaternary phase space has yielded three new compounds: KCuThS3 (I), K2Cu2ThS4 (II), and K3Cu3Th2S7 (III). All three phases are semiconductors with optical band gaps of 2.95, 2.17, and 2.49 eV(I-III). Compound I crystallizes in the orthorhombic space group Cmcm with a = 4.076(1) A, b = 13.864(4) A, and c = 10.541(3) A. Compound II crystallizes in the monoclinic space group C2/m with a = 14.522(1) A, b = 4.026(3) A, and c = 7.566(6) A; beta = 109.949(1) degrees . Compound III crystallizes in orthorhombic space group Pbcn with a = 4.051(2) A, b = 14.023(8) A, and c = 24.633(13) A. The compounds are all layered materials, with each layer composed of threads of edge-sharing ThS6 octahedra bridged by CuS4 tetrahedral threads of varying dimension. The layers are separated by well-ordered potassium ions. The relatively wide range of optical band gaps is attributed to the extent of the CuS4 motifs. As the dimension of the CuS4 chains increases, band gaps decrease in the series. All materials were characterized by single-crystal X-ray diffraction, microprobe chemical analysis, and diffuse reflectance spectroscopy (NIR-UV).

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“…The reactants were heated to 793 K in 1 d, held at 793 K for 7 d, cooled to 423 K in 8 d, and then cooled to 298 K in 4 h. The products were washed with DMF, and then dried with acetone. From both single crystal and X-ray powder diffraction measurements it was found that the products included black polyhedral-shaped Rb 6 Cu 12 U 2 S 15 crystals, red RbCuS 4 long needles, black RbCu 4 S 3 prisms, blue hexagonal CuS plates, and a black powder, which mainly consisted of US and β-US 2 . The yield of black polyhedra of Rb 6 Cu 12 U 2 S 15 was about 40 wt % based on Cu.…”

Section: Methodsmentioning

confidence: 99%

Oxidation State of Uranium in A₆Cu₁₂U₂S₁₅(A = K, Rb, Cs) Compounds

Malliakas

Yao²,

Wells³

et al. 2012

Inorg. Chem.

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Black single crystals of A(6)Cu(12)U(2)S(15) (A = K, Rb, Cs) have been synthesized by the reactive flux method. These isostructural compounds crystallize in the cubic space group Ia ̅3d at room temperature. The structure comprises a three-dimensional framework built from US(6) octahedra and CuS(3) trigonal planar units with A cations residing in the cavities. There are no S-S bonds in the structure. To elucidate the oxidation state of U in these compounds, various physical property measurements and characterization methods were carried out. Temperature-dependent electrical resistivity measurement on a single crystal of K(6)Cu(12)U(2)S(15) showed it to be a semiconductor. These three A(6)Cu(12)U(2)S(15) (A = K, Rb, Cs) compounds all exhibit small effective magnetic moments, < 0.58 μ(B)/U and band gaps of about 0.55(2) eV in their optical absorption spectra. From X-ray absorption near edge spectroscopy (XANES), the absorption edge of A(6)Cu(12)U(2)S(15) is very close to that of UO(3). Electronic band structure calculations at the density functional theory (DFT) level indicate a strong degree of covalency between U and S atoms, but theory was not conclusive about the formal oxidation state of U. All experimental data suggest that the A(6)Cu(12)U(2)S(15) family is best described as an intermediate U(5+)/U(6+) sulfide system of (A(+))(6)(Cu(+))(12)(U(5+))(2)(S(2-))(13)(S(-))(2) and (A(+))(6)(Cu(+))(12)(U(6+))(2)(S(2-))(15).

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The crystal structure of covellite

Cited by 11 publications

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Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Three New Phases in the K/Cu/Th/S System: KCuThS₃, K₂Cu₂ThS₄, and K₃Cu₃Th₂S₇

Oxidation State of Uranium in A₆Cu₁₂U₂S₁₅(A = K, Rb, Cs) Compounds

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The crystal structure of covellite

Cited by 11 publications

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Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study

Three New Phases in the K/Cu/Th/S System: KCuThS3, K2Cu2ThS4, and K3Cu3Th2S7

Oxidation State of Uranium in A6Cu12U2S15(A = K, Rb, Cs) Compounds

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Three New Phases in the K/Cu/Th/S System: KCuThS₃, K₂Cu₂ThS₄, and K₃Cu₃Th₂S₇

Oxidation State of Uranium in A₆Cu₁₂U₂S₁₅(A = K, Rb, Cs) Compounds