Common Edges Research Articles

Ternary indides RE 3 T 2In4 (RE=Dy–Tm; T=Pd, Ir)

Abstract The ternary rare earth transition metal-indides RE 3 T 2In4 (RE=Dy–Tm; T=Pd, Ir) were obtained from high-temperature reactions in sealed niobium ampoules. These indides adopt a hexagonal structure of the Lu3Co1.87In4 type (space group P6̅), a ternary ordered superstructure of the aristotype Fe2P. The structures of three different compounds were refined from single-crystal X-ray diffractometer data: a=768.20(6), c=381.97(3) pm, 1441 F 2 values, 24 parameters, wR2=0.0338 (Ho3Pd1.90In4); a=774.98(3), c=378.51(2) pm, 577 F 2 values, 23 parameters, wR2=0.0742 (Ho3Ir1.69In4.31) and a=780.3(1), c=369.4(1) pm, 573 F 2 values, 22 parameters, wR2=0.0403 (Tm3Ir1.51In4.49). Refinements of the occupancies revealed homogeneity ranges in case of the iridium-based crystals resulting from Ir/In mixing. The refined composition of the palladium compound was Ho3Pd1.90In4 resulting from defects on the Wyckoff position 1d, which was already reported for the prototype Lu3Co1.87In4. The geometrical motifs of the RE 3 T 2In4 structures are three different types of tricapped trigonal prisms around the transition metal and indium atoms which are condensed via common edges and triangular faces. Temperature dependent magnetic susceptibility measurements of Dy3Ir2In4 and Tm3Ir2In4 showed Curie-Weiss behavior and the experimental magnetic moments of 10.59(2) μB (Dy3Ir2In4) and 7.40(2) μB (Tm3Ir2In4) confirming stable trivalent RE 3+ states. Dy3Ir2In4 and Tm3Ir2In4 order antiferromagnetically with Néel temperatures of T N=13.6(5) and 5.4(5) K, respectively.

Comparison of metabolite networks from four German population-based studies.

BackgroundMetabolite networks are suggested to reflect biological pathways in health and disease. However, it is unknown whether such metabolite networks are reproducible across different populations. Therefore, the current study aimed to investigate similarity of metabolite networks in four German population-based studies.MethodsOne hundred serum metabolites were quantified in European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam (n = 2458), EPIC-Heidelberg (n = 812), KORA (Cooperative Health Research in the Augsburg Region) (n = 3029) and CARLA (Cardiovascular Disease, Living and Ageing in Halle) (n = 1427) with targeted metabolomics. In a cross-sectional analysis, Gaussian graphical models were used to construct similar networks of 100 edges each, based on partial correlations of these metabolites. The four metabolite networks of the top 100 edges were compared based on (i) common features, i.e. number of common edges, Pearson correlation (r) and hamming distance (h); and (ii) meta-analysis of the four networks.ResultsAmong the four networks, 57 common edges and 66 common nodes (metabolites) were identified. Pairwise network comparisons showed moderate to high similarity (r = 63–0.96, h = 7–72), among the networks. Meta-analysis of the networks showed that, among the 100 edges and 89 nodes of the meta-analytic network, 57 edges and 66 metabolites were present in all the four networks, 58–76 edges and 75–89 nodes were present in at least three networks, and 63–84 edges and 76–87 edges were present in at least two networks. The meta-analytic network showed clear grouping of 10 sphingolipids, 8 lyso-phosphatidylcholines, 31 acyl-alkyl-phosphatidylcholines, 30 diacyl-phosphatidylcholines, 8 amino acids and 2 acylcarnitines.ConclusionsWe found structural similarity in metabolite networks from four large studies. Using a meta-analytic network, as a new approach for combining metabolite data from different studies, closely related metabolites could be identified, for some of which the biological relationships in metabolic pathways have been previously described. They are candidates for further investigation to explore their potential role in biological processes.

Image-domain multimaterial decomposition for dual-energy CT based on prior information of material images.

Dual-Energy Computed Tomography (DECT) is of great interest in medical imaging, security inspection, and nondestructive testing. Most DECT reconstruction methods focus on producing two material images with different linear attenuation coefficients. However, the ability to reconstruct three or more basis materials is clinically and industrially important. Under the assumption that there are at most three materials in each pixel, there are a few methods that estimate multiple material images from DECT measurements by enforcing sum-to-one and a box constraint ([0 1]) derived from both the volume and mass conservation assumption. The recently proposed image-domain multimaterial decomposition (MMD) method introduces edge-preserving regularization for each material image. It enforces the assumption that there are at most three materials in each pixel using a time-consuming loop over all possible material triplets. However, this method neglects relations among material images. We propose a new image-domain MMD model for DECT that considers the prior information that different material images have common or complementary edges and encourages sparsity of material composition in each pixel using regularization. The proposed PWLS-TNV-ℓ0 method uses penalized weighted least-square (PWLS) reconstruction with three regularization terms. The first term is total nuclear variation (TNV) that accounts for the image property that basis material images share common or complementary boundaries and each material image is piecewise constant. The second term is an ℓ0 norm that encourages each pixel containing a small subset of material types out of several possible materials. The third term is a characteristic function based on sum-to-one and a box constraint derived from the volume and mass conservation assumption. We apply the Alternating Direction Method of Multipliers (ADMM) to optimize the cost function of the PWLS-TNV-ℓ0 method. We evaluated the proposed method on a simulated digital phantom, Catphan©600 phantom and patient's pelvis data. We implemented two existing image-domain MMD methods for DECT, the Direct Inversion and the PWLS-EP-LOOP method. We initialized the PWLS-TNV-ℓ0 method and the PWLS-EP-LOOP method with the results of the Direct Inversion method and compared performance of the proposed method with that of the PWLS-EP-LOOP method. The proposed method lowers the bias of decomposed material fractions by 84.47% in the digital phantom study, by 99.50% in the Catphan©600 phantom study, and by 99.64% in the pelvis patient study, respectively, compared to the PWLS-EP-LOOP method. The proposed method reduces noise standard deviation (STD) by 52.21% in the Catphan©600 phantom study, and by 16.74% in the patient's pelvis study, compared to the PWLS-EP-LOOP method. The proposed method increases volume fraction accuracy by 6.04%,20.55%, and 13.46% for the digital phantom, the Catphan©600 phantom, and the patient's pelvis study, respectively, compared to the PWLS-EP-LOOP method. Compared with the PWLS-EP-LOOP method, the root mean square percentage error [RMSE(%)] of electron densities in the Catphan©600 phantom is decreased by about 7.39%. We proposed an image-domain MMD method, PWLS-TNV-ℓ0 , for DECT. The PWLS-TNV-ℓ0 method takes low rank property of material image gradients, sparsity of material composition and mass and volume conservation into consideration. The proposed method suppresses noise, reduces cross contamination, and improves accuracy in the decomposed material images, compared to the PWLS-EP-LOOP method.

The crystal chemistry of Ce-rich compounds Ce4RuAl and Ce23Ru7+xAl4-x (0 ≤ x ≤ 2.97)

Novel Ce-rich phases Ce4RuAl and Ce23Ru7+xAl4-x (0 ≤ x ≤ 2.97) were found in the systematic investigation of the ternary Ce-Ru-Al system. Both compounds were investigated by scanning electron microscopy, EDX spectroscopy and X-ray diffraction methods. The Ce4RuAl compound crystallizes with a cubic structure of a Gd4RhIn type with lattice parameter a = 13.7709(8) Å (sp. gr. F-43m, Z = 16). Its crystal structure was determined from single crystal X-ray data (RF = 0.0241 for 741 independent reflections). The Ce23Ru7+xAl4-x structure was established by X-ray powder diffraction. This compound belongs to Pr23Ir7Mg4 structure type, space group P63mc. Cell parameters of Ce23Ru7+xAl4-x at x = 0.4 are: a = 9.8137(4) Å, c = 22.2010(13) Å. In both compounds Ce4RuAl and Ce23Ru7+xAl4-x some of the Ce-Ru distances are short, equal to 2.630 Å and 2.562 Å, respectively. Crystal chemistry of these intermetallics is characterized by packing of non-linear layers in which the Ru-centered trigonal [Ce6] prisms are connected via common vertices and edges, - similar to packing in the related Ce7Ru3 and La15Rh5Cd2 compounds.

Betaine (trimethylammonioacetate) binary compound with sodium iodide

In the title compound,catena-poly[[[bis[2-(trimethylazaniumyl)acetato-κO]sodium]-di-μ-aqua-[diaquasodium]-di-μ-aqua] diiodide], {[Na2(C5H11NO2)2(H2O)6]I2}n, both Na+ions have distorted octahedral environments (coordination number 6). The coordination polyhedra of the sodium ions are connected by common edges forming an infinite chain of ions along [100]. The chains and betaine zwitterions are assembled into infinitive layersviahydrogen bonds. These layers are connectedviaelectrostatic attraction between iodide ions and positive trimethylazanium groups in the crystal.

Renaissance of the Stella Quadrangula: The Lanthanoid Nitride Tellurides Ln13N5Te12 (Ln = La–Nd)

Ln13N5Te12 (Ln = La–Nd), a quite unusual composition of the lanthanoid(III) nitride tellurides, appears with a new crystal structure and can be obtained by reactions of lanthanoid metal (Ln) with elemental tellurium (Te), sodium azide (NaN3), elemental iodine (I2) and sodium iodide (NaI) as flux in evacuated fused silica tubes for seven days at 900 °C. The black, shard‐shaped single crystals of the short new series Ln13N5Te12 (Ln = La–Nd) crystallize monoclinically in the space group P21/m with lattice parameters ranging from a = 1039.86(7), b = 1373.29(9), c = 1311.78(9) pm, β = 100.103(3)° for La13N5Te12 to a = 1016.73(7), b = 1337.58(9), c = 1288.92(9) pm, β = 100.094(3)° for Nd13N5Te12 and Z = 2. Unlike the other ternary compounds of the lanthanoid(III) nitride tellurides, two different types of isolated oligomers containing edge‐sharing [NLn4]9+ tetrahedra occur in their crystal structure. The fusion of two [NLn4]9+ units via one common edge forms [N2Ln6]12+ bitetrahedra, which are already known from the Ln3NTe3 examples with Ln = Gd–Ho. In contrast, the [N3Ln7]12+ trimers built up by three [NLn4]9+ tetrahedra with two sharing edges for each [NLn4]9+ unit, but three common edges overall, represent a new highlight. Both kinds of oligomers can be traced back to a stella quadrangula [N4Ln8]12+ and are embedded in a dense matrix of Te2– anions according to {[Ln6N2][Ln7N3]Te12}.

Fiemmeite Cu2(C2O4)(OH)2∙2H2O, a New Mineral from Val di Fiemme, Trentino, Italy

The new mineral species fiemmeite, Cu2(C2O4)(OH)2∙2H2O, was found NE of the Passo di San Lugano, Val di Fiemme, Carano, Trento, Italy (latitude 46.312° N, longitude 11.406° E). It occurs in coalified woods at the base of the Val Gardena Sandstone (upper Permian) which were permeated by mineralizing solutions containing Cu, U, As, Pb and Zn. The oxalate anions have originated from diagenesis of the plant remains included in sandstones. The mineral forms aggregate up to 1 mm across of sky blue platelets with single crystals reaching maximum dimensions of about 50 μm. Associated minerals are: baryte, olivenite, middlebackite, moolooite, brochantite, cuprite, devilline, malachite, azurite, zeunerite/metazeunerite, tennantite, chalcocite, galena. Fiemmeite is monoclinic, space group: P21/c with a = 3.4245(6), b = 10.141(2), c = 19.397(3) Å, β = 90.71(1)°, V = 673.6(2) Å3, Z = 4. The calculated density is 2.802 g/cm3 while the observed density is 2.78(1) g/cm3. The six strongest reflections in the X-ray powder diffraction pattern are: [dobs in Å (I)(hkl)] 5.079(100)(020), 3.072(58)(112), 9.71(55)(002), 4.501(50)(022), 7.02(28)(012), 2.686(25)(114). The crystal structure was refined from single-crystal data to a final R1 = 0.0386 for 1942 observed reflections [I > 2σ(I)] with all the hydrogen atoms located from a Difference–Fourier map. The asymmetric unit contains two independent Cu2+ cations that display a distorted square-bipyramidal (4+2) coordination, one oxalate anion, two hydroxyl anions and two water molecules. The coordination polyhedra of the two copper atoms share common edges to form polymeric rows running along [100] with composition [Cu2(C2O4)(OH)2∙2H2O]n. These rows are held together by a well-established pattern of hydrogen bonds between the oxalate oxygens not involved in the coordination to copper, the hydrogen atoms of the water molecules and the hydroxyl anions.

EDS tomographic reconstruction regularized by total nuclear variation joined with HAADF-STEM tomography

Energy-dispersive X-ray spectroscopy (EDS) tomography is an advanced technique to characterize compositional information for nanostructures in three dimensions (3D). However, the application is hindered by the poor image quality caused by the low signal-to-noise ratios and the limited number of tilts, which are fundamentally limited by the insufficient number of X-ray counts. In this paper, we explore how to make accurate EDS reconstructions from such data. We propose to augment EDS tomography by joining with it a more accurate high-angle annular dark-field STEM (HAADF-STEM) tomographic reconstruction, for which usually a larger number of tilt images are feasible. This augmentation is realized through total nuclear variation (TNV) regularization, which encourages the joint EDS and HAADF reconstructions to have not only sparse gradients but also common edges and parallel (or antiparallel) gradients. Our experiments show that reconstruction images are more accurate compared to the non-regularized and the total variation regularized reconstructions, even when the number of tilts is small or the X-ray counts are low.

Luminescence of an Oxonitridoberyllate: A Study of Narrow-Band Cyan-Emitting Sr[Be6ON4]:Eu2+

Oxo- and (oxo)nitridoberyllates show exceptional potential as host lattices for application in illumination grade phosphor converted (pc)LEDs due to their remarkable electronic and structural characteristics, allowing highly efficient narrow-band emission upon doping with Eu2+. Sr[Be6ON4]:Eu2+, the first example of an oxonitridoberyllate phosphor, exhibits narrow-band cyan emission (λem = 495 nm; full width at half-maximum, fwhm = 35 nm; ≈1400 cm–1), comparable to the emission of the oxonitridosilicate BaSi2O2N2:Eu2+ (fwhm = 35 nm) or a cyan-emitting primary LED (fwhm = 27 nm). Sr[Be6ON4]:Eu2+ reveals a highly condensed rigid 3D network with a remarkably large degree of condensation [i.e., atomic ratio Be:(O,N)] of κ = 1.2 that is achieved by interconnection of highly condensed layers of BeN4 tetrahedra by Be2ON6 units via common edges. The crystal structure of Sr[Be6ON4]:Eu2+ was solved on the basis of single-crystal and powder XRD data (C2/c, no. 15, a = 13.9283(14), b = 5.7582(6), c = 4.9908(5) A, β = ...

Synthesis and crystal structures of the new ternary borides Fe3Al2B2and Ru9Al3B8and the confirmation of Ru4Al3B2and Ru9Al5B8−x(x≈2)

AbstractSingle crystals of the new ternary borides Fe3Al2B2and Ru9Al3B8were obtained from the elements at 1900°C. Both compounds represent new structure types which combine well-known features of binary and ternary borides of transition metals in combination with aluminum. The crystal structure of Fe3Al2B2(P2/m,Z=2,a=5.724,b=2.857,c=8.723 Å, β=98.57°) contains tetramers of face-sharing trigonal prisms BFe6with a B4unit in trans-configuration. The tetrameric units are separated by Al-atoms which occupy all remaining rectangular sites of the trigonal prisms. The structure can be derived from Fe2AlB2by insertion of additional FeAl fragments in abccarrangement. The crystal structure of Ru9Al3B8(P6̅2m,Z=1,a=9.078,c=2.913 Å) combines zig-zag chains of boron atoms made of face-sharing trigonal prisms BFe6and isolated BFe6units. Three of these chains are connected by common corners to rods running in direction [001]. The rods are linked to a three-dimensional framework by isolated prisms via common edges. Again, Al occupies the capping positions of the trigonal prisms. Ru9Al3B8is the second representative for the combination of boron zig-zag chains and isolated B atoms. The existence of Ru4Al3B2(P4/mmm,Z=2,a=8.515,c=2.924 Å) and Ru9Al5B8−x(P4/m,Z=1,a=8.741,c=2.923 Å) were confirmed and the crystal structures refined. High quality data reveal a stoichiometric composition for Ru4Al3B2, while in Ru9Al5B8−xthere is a significant underoccupation (i.e. x≈2) of the central boron site within the B4units. The crystal structures of all four compounds represent examples for the combination of CsCl and AlB2fragments as they were frequently found for ternary borides of transition metals.

The component interaction in the Hf–Fe–P system

Component interaction in Hf−Fe−P system has been studied using X-ray powder methods andisothermal sections of phase diagrams have been constructed at 1070 K in the range up to 67 at. % P. Study samples have been prepared from mixtures of Hf, Fe, and P powders, each of purity higher than 99.9 %, which have been pressed into pellets and subjected to appropriate heat treatment depending on phosphorus content. The samples with P content of less than 35 at. % have been synthesized in arc-furnace. The samples with P content of more than 35 at. % have been just sintered at 1070 K. All samples were annealed at 1070 K for 800 hours. The majority of binary compounds do not dissolve the third component. The exception is existence of substitution type solid solutions based on binary phosphides HfP 2 (structure type PbCl 2 , space group Рпта ) – Hf 0.715(5) Fe 0.285(5) P 2 ( а = 6.4555(1), b = 3.49236(5), c = 8.6283(1) Å) and HfP (structure type TiAs, space group TiP) – Hf 0.87(2) Fe 0.13(2) P ( а = 3.6401(1), c = 12.3365(4) Å). In homogeneity ranges of ternary and binary phases, the substitution of hafnium by ferrum takes place. The three ternary compounds exist in Hf-Fe-P system at this temperature. Two of them have homogeneity regions and their compositions can be represented as Hf 1.20-0.85 Fe 0.80-1.15 P (structure type TiNiSi, space group Pnma , а = 6.256(2)−6.229(2), b = 3.717(1)−3.7058(9), c = 7.152(2)−7.111(2) Å) and Hf 4.1-3.7 Fe 0.9-1.3 P (structure type Nb 4 CoSi, space group P 4/ mcc , а =6.418(1)−6.397(2), с = 0.5246(2)−0.5225(2) Å). The crystal structure investigation of the new ternary phosphide Hf 2 Fe 4 P 3 has been performed by means of X-ray powder method. This compound is isotypical to the Hf 2 Co 4 P 3 -type structure (space group Р -62 m , a = 11.972(2), c = 3.5941(7)Å). In the two-layered structure of Hf 2 Fe 4 P 3 compound, P atoms are located inside trigonal prisms, which are built from six metal atoms with three additional atoms in front of the rectangular faces. These trigonal prisms, connected to each other with bases, form columns along the c direction. The columns of prisms are joined by common edges in winding closed channels. Keywords: phosphide, phase equilibrium, substitution type solid solution.

The flow boiling heat transfer coefficient determination in a minichannel used the FEM combined with Trefftz functions

The method of solving the inverse heat conduction problem, by means of the FEM with Trefftz-type basis functions, during flow boiling in a minichannel was shown. This basis functions were constructed with using the Hermite interpolation and Trefftz functions. The aim of the numerical calculations was to determine the local heat transfer coefficient on the basis of experimental data in a horizontally oriented minichannel. The refrigerant flowing along the minichannel (HFE-649 or HFE-7100) was heated by a thin enhanced plate by vibration-assisted laser texturing. The temperature on an outer smooth side of the plate was detected by means of infrared thermography. On the heated wall–fluid contact surface in the minichannel the heat transfer coefficient was obtained from the Robin boundary condition. It was assumed that the temperature distribution in the heated plate was described by the Poisson equation. The unknown values of temperature and temperature derivatives at nodes were computed by minimizing the functional which describes the mean square error of the approximate solution on the boundary and along common edges of neighbouring elements. The results were presented as the heated plate temperature and heat transfer coefficient versus the minichannel length.

Bifurcated configurations and their variations of an 8-bar linkage derived from an 8-kaleidocycle

The paper presents an eight-bar linkage derived from a rotatable kaleidocycle, a hinged ring of eight regular tetrahedra with revolute joint axes along common edges. A thorough kinematics study of this eight-bar linkage is conducted with screw system approach and the kinematics closure equation is derived in a simplified way. The bifurcated motion of this two-degree-of-freedom linkage is explored in the joint space for the first time. Based on the sagittal planes of the joint space, the bifurcated sub-motions of a special line and plane symmetric Bricard linkage are analyzed.

Structural similarity and difference testing on multiple sparse Gaussian graphical models

We present a new framework on inferring structural similarities and differences among multiple high-dimensional Gaussian graphical models (GGMs) corresponding to the same set of variables under distinct experimental conditions. The new framework adopts the partial correlation coefficients to characterize the potential changes of dependency strengths between two variables. A hierarchical method has been further developed to recover edges with different or similar dependency strengths across multiple GGMs. In particular, we first construct two-sample test statistics for testing the equality of partial correlation coefficients and conduct large-scale multiple tests to estimate the substructure of differential dependencies. After removing differential substructure from original GGMs, a follow-up multiple testing procedure is used to detect the substructure of similar dependencies among GGMs. In each step, false discovery rate is controlled asymptotically at a desired level. Power results are proved, which demonstrate that our method is more powerful on finding common edges than the common approach that separately estimates GGMs. The performance of the proposed hierarchical method is illustrated on simulated datasets.

Dynamic stiffness formulation for the vibrations of stiffened plate structures with consideration of in-plane deformation

A dynamic stiffness method is presented for the vibrations of plate structures that are reinforced by eccentric stiffeners. The model incorporates both out-of-plane and in-plane deformations of the plates and the stiffeners. Based on the relationship between the forces and displacements along the common edges of the plate or beam elements, the dynamic stiffness formulae for the plate and the beam elements are derived, respectively. The globally assembled dynamic stiffness matrix is then obtained using the finite element method so that the dynamics of built-up stiffened plates can be readily addressed by using the present method. Compared to the conventional finite element model, the dynamic stiffness model can provide very accurate solutions using only one element over each uniform plate and beam member, regardless of its geometry.

Finding shortest paths in a sequence of triangles in 3D by the method of orienting curves

We present an efficient algorithm for finding the shortest path joining two points in a sequence of triangles in three-dimensional space without planar unfolding. The concept of a funnel associated with a common edge along a sequence of triangles is introduced, that is similar to Lee and Preparata’s one in a simple polygon. The sequence of funnels associated with all common edges of the sequence is constructed and then the shortest path is determined by cusps of these funnels. Such funnels are determined iteratively to their associated edges by the Method of Orienting Curves, which was introduced by Phu [Ein konstruktives Lösungsverfahren für das Problem des Inpolygons kleinsten Umfangs von J. Steiner. Optimization. 1987;18:349–359]. The method consists of the concepts of final curves and orienting curves (the special cases of straightest geodesics). We then show that the shortest path from the cusp of a given funnel to the direct destination in the processed region of the funnel is determined by parts of orienting curves and a final curve. A numerical example for finding the shortest path joining two points in the sequence of triangles is presented and visualized by JavaView software.

Reaction mechanism, rate constants, and product yields for the oxidation of Cyclopentadienyl and embedded five-member ring radicals with hydroxyl

Potential energy surfaces for the C5H5 + OH and C15H9 + OH reactions have been studied by ab initio calculations at the CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) and G3(MP2,CC)//B3LYP/6-311G(d,p) levels of theory, respectively, in order to unravel the mechanism of oxidation of the cyclopentadienyl radical and five-member-ring radicals embedded in a sheet of six-member rings with OH. The VRC-TST approach has been employed to compute high-pressure-limit rate constants for barrierless entrance and exit reaction steps and multichannel/multiwell RRKM-ME calculations have been utilized to produce phenomenological pressure- and temperature-dependent absolute and individual-channel reaction rate constants. The calculations allowed us to quantify relative yields of various products in a broad range of conditions relevant to combustion and to generate rate expressions applicable for kinetic models of oxidation of aromatics. The C5H5 + OH reaction is shown to proceed either by well-skipping pathways without stabilization of C5H6O intermediates leading to the bimolecular products ortho-C5H5O + H, C5H4OH (hydroxycyclopentadienyl) + H, and C4H6 (1,3-butadiene) + CO, or via stabilization of the C5H6O intermediates, which then undergo unimolecular thermal decomposition to ortho-C5H5O + H and C4H6 + CO. The well-skipping and stabilization/dissociation pathways compete depending on the reaction conditions; higher pressures favor the stabilization/dissociation and higher temperature favor the well-skipping channels. For the C15H9 + OH reactions, the results demonstrate that embedding decreases the oxidation rate constants and hinder the decarbonylation process; the removal of CO grows less likely as the number of common edges of the five-member ring with the surrounding six-member rings increases.

CuTiPS5 – A New Structure Type with a Corrugated Layered Network Structure

The reaction of the binary sulfides TiS2 and P4S10 with the elements Cu and S for 10 h at 750 °C and subsequent annealing at 550 °C for 21 d result in the novel compound CuTiPS5, which crystallizes in the triclinic space group P1 with a = 6.8381(12), b = 6.9905(12), c = 14.612(3) Å, α = 90.057(6)°, β = 101.771(7)°, γ = 103.165(7)°, Z = 4, R1 = 1.87 %, wR2 = 4.74 % (all reflections) and represents the first quaternary copper titanium thiophosphate. The crystal structure contains 1∞[Cu2Ti2(PS4)2S2] chains built from TiS6 octahedra and PS4 and CuS4 tetrahedra, which are connected by common edges and linked via common vertices to form layers. The anionic [TiPS5]– partial structure has been found previously, whereas the distinct 2D extension of the network is observed for the first time in compounds with such a MTiPS5 composition. The structure resembles sections of the TiS2 and Cu3PS4 structures, which were found in the reaction as by‐products.

The Crystal Structure of Nitridomagnesogermanate Ba[Mg3GeN4]:Eu2+ and Theoretical Calculations of Its Electronic Properties

Nitridomagnesogermanate Ba[Mg3GeN4]:Eu2+ was synthesized by the NaN3 route in weld‐shut tantalum ampules by reaction of the elements in molten sodium with NaN3 as nitrogen source at 780 °C. The crystal structure was solved and refined on the basis of single‐crystal X‐ray diffraction data. Ba[Mg3GeN4]:Eu2+ crystallizes in the UCr4C4 structure type [space group I4/m (no. 87), a = 8.3921(12), c = 3.4813(7) Å, Z = 2] and exhibits a highly condensed anionic network made up of statistically disordered (Mg/Ge)N4 tetrahedra, which are connected to each other by common vertices and edges to form vierer ring channels along [001]. Ba2+ is located in every second channel and has cubelike coordination by eight N atoms. Theoretical calculations of the electronic properties of Ba[Mg3GeN4]:Eu2+ are discussed to understand the absence of photoluminescence in the visible range and for comparison with other luminescent materials that are structurally related to Ba[Mg3GeN4]:Eu2+.

Synthesis and crystal structure of a new magnesium phosphate Na3RbMg7(PO4)6.

A new magnesium phosphate, Na3RbMg7(PO4)6 [tris-odium rubidium hepta-magnesium hexakis(ortho-phosphate)], has been synthesized as single crystals by the flux method and exhibits a new structure type. Its original structure is built up from MgO x (x = 5 and 6) polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetra-hedra. The resulting anionic three-dimensional framework leads to the formation of channels along the [010] direction, in which the Na+ cations are located, while the Rb+ cations are located in large inter-stitial cavities.