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The new, quaternary diamond-like semiconductor (DLS) Cu

While X-ray powder diffraction (XRPD) is a fundamental analytical technique used by solid-state laboratories across a breadth of disciplines, it is still underrepresented in most undergraduate curricula. In this work, we incorporate XRPD analysis into an inquiry-based project that requires students to identify the crystalline component(s) of familiar household products. Centering the project on materials which students encounter in their everyday lives helps to demystify the technique, making it accessible to everyone with a basic understanding of crystallinity and unit cells. In an XRPD study, each crystalline component generates a unique set of peaks in the diffractogram. Comparing the collected diffractogram to a library of diffractograms for known crystalline materials allows students to identify the crystalline components in their unknown. Students must determine for themselves the chemical compositions of the possible unknowns, and link their findings back to the analysis of the collected data. Init...

Iron-containing diamond-like materials Ag2FeSiS4, Li2FeSnS4, and Li2FeGeS4 were synthesized for the first time via high-temperature, solid-state synthesis and found to adopt the wurtz–kesterite structure, crystallizing in the noncentrosymmetric space group Pn. These materials are considered in the broader context of design principles for new cubic- and hexagonal-derived diamond-like materials. All three of these new compounds violate Pauling’s radius ratio rule and Pfitzner’s tetrahedral volume theory. An evaluation of the adherence of over 40 published quaternary diamond-like structures to Pauling’s radius ratio rule and Pfitzner’s tetrahedral volume theory reveals that tetrahedral structures can often be generated even though these ideals are violated. To assess the radius ratios in diamond-like structures, an appropriate radii set must be selected. Accordingly, five radii sets have been investigated for accuracy in predicting metal–sulfur bond distances in diamond-like materials. Furthermore, a crystal radius of 1.63 A for four-coordinate S2− has been calculated using the metal–sulfur bond lengths of quaternary diamond-like materials and is proposed as an addition to the popular Shannon radii set.

Nitric oxide, a byproduct of combustion exhaust, is a key species that leads to urban photochemical smog. Nitric oxide exhibits low aqueous solubility, and it has proved difficult to remove NO from gas streams by aqueous scrubbing methods. A catalyst for the aqueous disproportionation of NO to nitrous oxide and aqueous nitrite has been developed with wood-derived activated carbons. Addition of palladium or platinum metal to the carbon support significantly accelerates catalysis. The carbon-supported catalyst was not poisoned by sulfur oxides. The reaction is thought to involve the reduction of surface-bound nitric oxide dimers. The reducing equivalents stem from the oxidation of NO to NO2-. Addition of oxygen as an alternative electron acceptor during the reaction immediately arrested nitrous oxide formation, and all the nitric oxide was removed from the gas stream as aqueous nitrite. This demonstrates the feasibility of removing SOx and NOx simultaneously by low-temperature aqueous scrubbing.

The decomposition of aqueous ammonium nitrate at elevated temperatures and pressures is examined as a function of chloride, nitrate, and total acidity. Catalysis requiring both chloride and acid wa...

Kinetics data were collected for the palladium-catalyzed reduction of nitric oxide (NO) to nitrous oxide (N2O) with cuprous chloride reductant in 2 M hydrochloric acid (2NO + 2CuCl + 2HCl → N2O + 2...

Single crystalline diamond-like Ag2FeSiS4 (I), Li2FeSnS4 (II), and Li2FeGeS4 (III) are prepared by solid state reaction of stoichiometric mixtures of Li2S and the respective elemental powders (graphite crucible in evacuated silica tube, 700 °C, 4 d).

Reductive carbonylation of TaCl(5) in the presence of 1,2-bis(diphenylphosphino)ethane (dppe) under the appropriate conditions results in the formation of TaCl(CO)(2)(dppe)(2) (1), as the major product, and the possibly cyclic oligomer [TaCl(CO)(2)(dppe)(2)](2)(x)() (2, 2x/= 4) as a minor product. Carbonylation of 1 (1 atm) results in the rapid but reversible formation of TaCl(CO)(4)(dppe) (3). Solutions of all three compounds exhibit low levels of paramagnetism, possibly attributable to thermal population of low-lying triplet excited states. Crystal data for the toluene solvate of 1, C(68)H(64)ClO(2)P(4)Ta: triclinic, Ponemacr; (No. 2), a = 13.937(12) Å, b = 14.811(7) Å, c = 14.929(9) Å, alpha = 102.30(5) degrees, beta = 95.60(7) degrees, gamma = 98.41(5) degrees, Z = 2.

The identity of a palladium chloronitrosyl complex, active in the catalytic reduction of NO to N 2 O, has been examined in aqueous and non-aqueous media. Stoichiometry experiments for its formation from [PdCl 4 ] 2− show the presence of one bound nitrosyl group per palladium and the requirement of a one-electron reductant, provided by CuCl. Work in non-aqueous solvents identified [Pd 2 Cl 4 (NO) 2 ] 2− as a key intermediate, although in aqueous 2 M HCl the monomeric form [PdCl 3 (NO)] 2− is suggested to predominate, according to the equilibrium: [Pd 2 Cl 4 (NO) 2 ] 2− + 2Cl − ⇄[PdCl 3 (NO)] 2− . The [Ph 4 As] 2 [Pd 2 Cl 4 (NO) 2 ] complex could be oxidized to the stable compound [Ph 4 As] 2 [Pd 2 Cl 4 (NO) 2 ) 2 ], whose structure was determined by single crystal X-ray diffraction.

Dielectric constants and indices of refraction of aqueous mixtures of the homologous series of polyoxyethene glycol mono-n-butyl ethers C 4 H 9 O(CH 2 CH 2 O) m H (where m = 1 to 3) were measured. From the experimental data, excess dielectric permittivities, dielectric molar susceptibilities, molar and molar orientational polarizabilities were evaluated. Also excess Lorentz-Lorentz molar refractions were evaluated and the results were discussed in terms of departure from ideality and intermolecular interactions in the mixtures

The asymmetric unit of the title compound, (C(6)H(20)N(4))(2)[Sn(2)S(6)], comprises half of a [Sn(2)S(6)](4-) anion and a diprotonated tris-(2-amino-eth-yl)amine cation. The anion lies on an inversion center, while the atoms of the cation occupy general positions. An intra-molecular N-H⋯N hydrogen bond is observed in the cation. In the crystal, strong N-H⋯S hydrogen bonding between the terminal sulfur atoms of the anion and the protonated amine N atoms of the cations result in a three-dimensional network.

Viscosities and densities of binary liquid mixtures containing 2-butoxyethanol as one component and aniline or N -alkylaniline as the other component have been measured over the whole composition range at five different temperatures. McAllister's approach correlates the viscosity data with a significantly high degree of accuracy for all these systems. From the experimental results, the excess volume, excess viscosity and excess molar free energy of activation of flow have been evaluated and the departure from ideal behaviour is explained on the basis of specific interactions between the components in these mixtures.

The preparation of tetrasodium uranyl trisulfate Na 4 UO 2 (SO) 4 ) 3 , in the glass state and its novel transformation via a stable intermediate state to the crystalline state, i.e. glass → intermediate → crystal is reported for the first time. The results from differential scanning calorimetry (DSC), infrared spectroscopy and X-ray powder diffraction show the intermediate as a pseudo-crystalline state, an incipient phase to its final crystal state. The intermediate → crystal transition does not show a measurable latent heat, ΔH t , thereby suggesting a non-first order transition type.