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A recent study has shown the thermoelectric performance of Al-doped Mg2Si materials can be significantly enhanced at moderate pressure. To understand the cause of this phenomenon, we have performed in situ angle dispersive X-ray diffraction and infrared reflectivity measurements up to 17 GPa at room temperature. Contrary to previous experiment, using helium as a pressure transmission medium, no structural transformation was observed in pure Mg2Si. In contrast, a phase transition from cubic anti-fluorite (Fm-3m) to orthorhombic anti-cotunnite (Pnma) was observed in the Al-doped sample at 10 GPa. Infrared reflectivity measurements show the electrical conductivity increases with pressure and is further enhanced after the phase transition. The electron density of states at the Fermi level computed form density functional calculations predict a maximum thermo-electric power factor at 1.9 GPa, which is in good agreement with the experimental observation. [ABSTRACT FROM AUTHOR]

The coordination of Mg2+ with the triphosphate group of adenosine triphosphate (ATP) in motor proteins is investigated using data mining and molecular dynamics. The possible coordination structures available from crystal data for actin, myosin, RNA polymerase, DNA polymerase, DNA helicase, and F1-ATPase are verified and investigated further by molecular dynamics. Coordination states are evaluated using structural analysis and quantified by radial distribution functions, coordination numbers, and pair interaction energy calculations. The results reveal a diverse range of both transitory and stable coordination arrangements between Mg2+ and ATP. The two most stable coordinating states occur when Mg2+ coordinates two or three oxygens from the triphosphate group of ATP. Evidence for five-site coordination is also reported involving water in addition to the triphosphate group. The stable states correspond to a pair interaction energy of either ~-2750 kJ/mol or -3500 kJ/mol. The role of water molecules in the hydration shell surrounding Mg2+ is also reported. [ABSTRACT FROM AUTHOR]

Crystalline structures of magnesium hexaboride, MgB6, were investigated using unbiased structure searching methods combined with first principles density functional calculations. An orthorhombic Cmcm structure was predicted as the thermodynamic ground state of MgB6. The energy of the Cmcm structure is significantly lower than the theoretical MgB6 models previously considered based on a primitive cubic arrangement of boron octahedra. The Cmcm structure is stable against the decomposition to elemental magnesium and boron solids at atmospheric pressure and high pressures up to 18.3 GPa. A unique feature of the predicted Cmcm structure is that the boron atoms are clustered into two forms: localized B6 octahedra and extended B∞ ribbons. Within the boron ribbons, the electrons are delocalized and this leads to a metallic ground state with vanished electric dipoles. The present prediction is in contrast to the previous proposal that the crystalline MgB6 maintains a semiconducting state with permanent dipole moments. MgB6 is estimated to have much weaker electron-phonon coupling compared with that of MgB2, and therefore it is not expected to be able to sustain superconductivity at high temperatures. [ABSTRACT FROM AUTHOR]

The formation, structure and deuterium desorption properties of Mg2FexCo(1−x)Dy (0 ≤ x ≤ 1 and 5 ≤ y ≤ 6) complex hydrides were investigated. The synthesis was carried out by reactive ball milling, using a mixture of powders of the parent elements in D2 atmosphere. The formation of quaternary deuterides was identified from Rietveld refinements of powder X-Ray diffraction and powder neutron diffraction patterns, and from infrared attenuated total reflectance analysis. It was observed that the crystal structure of deuterides depends on the transition metal fraction. For Co-rich compositions, i.e. up to x = 0.1, hydrides have the tetragonal distorted CaF2-type structure (space group P4/nmm) of Mg2CoD5 at room temperature. For Fe-rich compositions, i.e. x ≥ 0.5, a cubic hydride is observed, with the same K2PtCl6-type structure (space group Fm 3 ¯ m) as Mg2FeD6 and as Mg2CoD5 at high temperatures. For x = 0.3, both the cubic and the tetragonal deuterides are detected. Differential scanning calorimetry coupled with thermogravimetric and temperature programmed desorption analyses show rather similar deuterium desorption properties for all samples, without significant changes as a function of composition. Finally, hydrogen sorption experiments performed for Mg2Fe0.5Co0.5H5.5 at 30 bar of H2 and 673 K showed reversible reactions, with good kinetic for both absorption and desorption of hydrogen. [ABSTRACT FROM AUTHOR]

Abstract Thermally conductive composites aimed for dielectric application were achieved by embedding spherical MgSiO 3 -SiO 2 -hBN powders into cyanate ester resin as functional fillers. The MgSiO 3 -SiO 2 -hBN particles were prepared by plasma sythesized process employing talc and hexagonal boron nitride (hBN) as sources. The morphology, phase structure of the MgSiO 3 -SiO 2 -hBN powders were characterized by changing the content of BN. Meanwhile, the thermal and dielectric properties of the composites with different filler loading were investigated. Results show that phase transformation from talc to protoenstatite and critobalite occurred. The thermal conductivity shows a drastic enhancement with the increase of the filler loading. Further contrast analyzed by Bruggeman model shows that the tested values agree well with estimated ones when fillers fraction are less than 15 vol%. However, an obvious deviation for the values of thermal conductivities is thought to arise from the randomly oriented hBN and the formation of the thermal conductive networks in composites. Relatively low dielectric constants and dielectric losses (tanδ) are obtained for all the composites. [ABSTRACT FROM AUTHOR]

Abstract The aim of the study was to determine the influence of Mg excess on the physicochemical properties with particular emphasis on thermoelectric properties of synthesized Mg 2 Si. Available literature devoted to this issue suggests very often a need to use an excess of Mg during the synthesis process in order to obtain homogeneous material [ 1–13 ]. Samples with 0–10 wt% of excessive Mg were prepared using the Spark Plasma Sintering (SPS) method. The structural and phase compositions were examined using X -ray diffraction XRD and scanning electron microscopy SEM coupled with EDS detector for the chemical composition analysis. The influence of Mg content on the impedance spectrum and transport properties, i.e. : electrical conductivity, the Seebeck coefficient and the thermal conductivity was studied in temperature range from 300 to 720 K. Carrier concentration was measured using Hall method. Scanning thermoelectric microprobe (STM) was used to determine the uniformity of Seebeck coefficient. Furthermore, the temperature dependences of the thermoelectric figure of merit ZT were calculated. The experiments performed, allow concluding that Mg excess which is in liquid phase during the sintering process gathers mostly at the grain boundaries, enhancing sintering process and decreasing total porosity of the samples. Moreover, higher Mg content increases electrical and thermal conductivity of Mg 2 Si, what causes simultaneous decrease of Seebeck coefficient. Step change in the electrical conductivity between the samples without and with the excess of magnesium (e.g. σ = 30 S m−1 for 0 wt% and σ = 1.26 · 105 S m−1 for 10 wt%) indicates the presence of a percolating mechanism. Highlights • SPS technique was used for synthesis and sintering of Mg 2+x Si samples. • Comprehensive study of structural and microstructural properties were examined. • Comprehensive examination of thermoelectric transport properties were studied. • Percolation mechanism of electrical conductivity was found. [ABSTRACT FROM AUTHOR]

Abstract A 0.31 mm-diameter Mg-6 wt% Zn alloy wire with high ultimate tensile strength of 300 MPa and elongation of 11% was successfully prepared via combination of extrusion, ECAP and hot drawing. Its excellent mechanical properties were attributed to the homogeneous and near single-phase microstructure. [ABSTRACT FROM AUTHOR]

Abstract Mn 1-x Zn x Fe 2 O 4 (0 ≤ x ≤ 0.7) nanoparticles were synthesised by a hydrothermal process. X-ray diffraction patterns reveal that all samples have spinel crystalline structures. Scanning electron microscopy and X-ray diffraction patterns show that nanoparticles are near-spherical in morphology and their average size is 13–45 nm. The elemental analysis was carried out by energy dispersive X-ray analysis technique. The optical direct band gap of Mn 1-x Zn x Fe 2 O 4 nanoparticle decreases from 2.38 to 1.88 eV as the Zn content increases. Moreover, the saturation magnetisation at room temperature tends to decrease with increasing Zn content. The specific absorption rate (SAR) values were measured at a fixed frequency of 178 kHz with magnetic field amplitude of 80 Oe. The SAR initially decreases with the sample concentration and its decrease is attributed to the enhancement of dipolar interaction and agglomeration of the particles. The intrinsic loss power (ILP) value varies between 6.5 and 15 nHm2kg−1 in the biologically safe experimental limit of 1.13 × 109Am−1s−1. The high value of ILP makes these nanoparticles possible for potential candidates for treating magnetic hyperthermia. Highlights • sGrain size decreases as the Zn2+ concentration increases. • FTIR, Raman and spectra used to characterize the samples.. • The optical band gap were calculated using UV-Vis diffuses reflectance spectra. • M s and T C values decreases dramatically when Zn2+ doping increases.. • ILP value varies between 6.5−15 nHm2kg−1, indicating Mn-Zn ferrite NPs can be used for magnetic hyperthermia. [ABSTRACT FROM AUTHOR]

In recent years, ternary transition metal oxides (TTMOs), especially spinel type TTMOs have attracted widespread attention as promising candidates for electrode materials. Among all of the popular TTMOs, MgCo2O4 is an outstanding one, owing to its superior theoretical capacitance. In this work, MgCo2O4 nanosheet arrays (NSAs) grown directly on nickel foams were fabricated through a facile hydrothermal process at 120 °C for 4 h. With a series of structural and morphological characterization techniques, it was found that the ethanol played a key role in controlling the composition and morphology during the synthesis process. The MgCo2O4 NSAs exhibited a superior specific capacitance of 853.06 C g−1 (at 1 mA cm−2) and enhanced cycling performance, with 94.65 % of initial capacitance retained after 3000 cycles when used as a binder‐free integrated electrode for electrochemical supercapacitors; much higher than other reported data for MgCo2O4 as well. The excellent electrochemical properties mainly came from the unique morphology of the MgCo2O4 NSAs. This study will demonstrate the applications of MgCo2O4 NSAs based large‐scale supercapacitors grown on low‐cost nickel foams. Foam party: MgCo2O4 nanosheet arrays have been prepared on a Ni foam substrate through a facile one‐step hydrothermal method and used as a binder‐free electrode material for supercapacitors. The MgCo2O4 NSAs electrode exhibits an electrochemical capacitance up to 853.06 C g−1 (at 1 mA cm−2) and about 94.65 % of the capacitance was retained after 3000 cycles (at 10 mA cm−2). [ABSTRACT FROM AUTHOR]

Magnetic chitosan/Cu-Mg-Al layered double hydroxide (mCSLDH) nanocomposite was prepared and copper(II) ions were immobilized in the prepared composite. The nanocomposite [(Cu-mCSLDH)] was characterized by FT-IR, XRD, VSM, AAS, EDX, SEM and TEM. The utility of nanocomposite was investigated in the one-pot three-component (A3) coupling of aldehydes, amines and alkynes to produce propargylamines. The Cu-mCSLDH nanocomposite is found to be highly efficient and recyclable heterogeneous catalyst. [ABSTRACT FROM AUTHOR]

Infrared (IR) guided missiles are real threat; they caused 90% of aircraft damage. Fluorocarbon polymer nanocomposite based on super-thermites can offer superior thermal signature to countermeasure IR guided missile seekers. This study reports on the sustainable fabrication of mono-dispersed colloidal Fe2O3 nanoparticles with 3 nm average particle size. Fe2O3 nanoparticles were dispersed in acetone for subsequent integration in fluorocarbon polymer. The impact of Fe2O3 content on thermal signature was evaluated using (FT-MIR 2-6 μm) spectrophotometer. Nanocomposite polymer with 8 wt% Fe2O3 offered an increase in the average intensity of α (2-3 μm) and β (4-5 μm) bands by 50 and 85% respectively to that of reference formulation. Quantification of stimulated emitting species in the combustion flame was conducted using ICT thermodynamic code. The developed nanothermite particles extended the primary reaction zone by 183%. Full discussions about combustion zones with associated exothermic chemical reactions have been represented. [ABSTRACT FROM AUTHOR]

Recently, binary metal oxides have been proven to be the most investigated semiconductors due to their high activity for the removal of organic pollutants. In this paper, to improve the photocatalytic efficiency of MgFe2O4, a MgFe2O4/reduced graphene oxide (MFO/rGO) photocatalyst was synthesized by a facile generalized solvothermal method. The morphology, structure, and photocatalytic activities in the degradation of methyl orange (MO) reaction were systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and UV-vis absorption spectroscopy, respectively. The results showed that the MFO/rGO composite exhibited enhanced photocatalytic performance in the photodegradation of MO under visible-light irradiation and reached a maximum degradation rate of 99% within 60 min of irradiation. This excellent photocatalytic performance is attributed to the introduction of rGO in the composite, which can effectively reduce the photoproduction of the electron-hole pair recombination rate. The excellent photocatalytic activity reveals that the MFO/rGO composite photocatalyst is a promising photocatalyst with good visible-light response and has potential applications in the field of water treatment. [ABSTRACT FROM AUTHOR]

A novel in-situ synthesis technique has previously been proposed for the synthesis of magnesium based nanocomposites, by exploiting the thermodynamic reactions, to fabricate nanoparticles in-situ during the melt processing. Although the microstructural aspects of formation of such nanocomposites have been dealt with previously, the implications of the same on the texture and hence on mechanical properties are not certain. In the present work, the evolution of crystallographic texture and its influence on tension-compression asymmetry (Tensile yield strength ÷ Compressive yield strength) and thereby, the impact on fatigue failure mechanisms is studied by comparing the behaviour of Mg-1.8Y/1.53ZnO nanocomposite and its monolithic alloy, Mg-1.8Y. The Mg-1.8Y/1.53ZnO nanocomposite revealed a very strong two component texture, not akin to the weak texture of Mg-1.8Y alloy. The texture was attributed to the loss of Y in the matrix and consumption of Y in formation of Y 2 O 3 nanoparticles in-situ and the formation of the β 1 ′ (Mg-Zn′) rods during extrusion. Further, this texture exhibited by the nanocomposite favoured high twinning activity under compression, thereby causing strong asymmetry in the tensile and compressive yield strengths. The fatigue tests indicated a superior performance of the nanocomposite as compared to the alloy. The deformation and damage mechanisms, when studied in correlation with the asymmetry revealed that the asymmetric materials exhibit steeper S-N curves as compared to the symmetric materials. [ABSTRACT FROM AUTHOR]

Using plane-wave pseudopotential density functional theory (DFT), the first-principle calculations are performed to investigate the structural aspects, mechanical behaviors and electronic features of the newly synthesized CaAl 2 Si 2 -prototype intermetallic compound, MgAl 2 Ge 2 for the first time and the results are compared with those calculated for its silicide and carbide counterparts MgAl 2 Si 2 and MgAl 2 C 2 . The calculated lattice constants agree fairly well with their corresponding experimental values. The estimated elastic tensors satisfy the mechanical stability conditions for MgAl 2 Ge 2 along with MgAl 2 Si 2 and MgAl 2 C 2 . The level of elastic anisotropy increases following the sequence of X -elements Ge → Si → C. MgAl 2 Ge 2 and MgAl 2 Si 2 are expected to be ductile and damage tolerant, while MgAl 2 C 2 is a brittle one. MgAl 2 Ge 2 and MgAl 2 Si 2 should exhibit better thermal shock resistance and low thermal conductivity and accordingly these can be used as thermal barrier coating (TBC) materials. The Debye temperature of MgAl 2 Ge 2 is lowest among three intermetallic compounds. MgAl 2 Ge 2 and MgAl 2 Si 2 should exhibit metallic conductivity; while the dual characters of weak-metals and semiconductors are expected for MgAl 2 C 2 . The values of theoretical Vickers hardness for MgAl 2 Ge 2 , MgAl 2 Si 2 , and MgAl 2 C 2 are 3.3, 2.7, and 7.7 GPa, respectively, indicating that these three intermetallics are soft and easily machinable. [ABSTRACT FROM AUTHOR]

In the present paper, Mg-substituted hydroxyapatites with the morphology, composed of the stacked plate- and rod-like structures, were prepared at the temperature of 600 °C by combustion method using glycerine as a fuel. A significant decrease in the crystallite size values calculated for both Scherrer and Williamson-Hall methods is found. The crystallinity, lattice parameter of a , stress and anisotropic energy density values decreased by adding of Mg, whereas the lattice strain increased. The amount of HAp phase decreases with increasing amount of Mg and the β -tricalcium phosphate content increases. Mg incorporation the apatitic structure was detected. Depending on the increase in Mg content, Ca-deficiency was observed. [ABSTRACT FROM AUTHOR]

Hierarchical MgAPO-11 molecular sieves with large BET surface areas and high pore volumes have been synthesized via dry-gel conversion of the magnesioaluminophosphate-carbon (MAP-C) composites. The carbon film coated on the mesopores of amorphous magnesioaluminophosphate (MAP) provides a confined-space to restrict the overgrowth of the crystals. The products were well characterized using XRD, SEM, TEM, N 2 adsorption-desorption, infrared spectroscopy of pyridine adsorption (Py-IR) and solid-state NMR techniques. The results show that highly mesoporous MgAPO-11 with good crystallinity can be obtained at an appropriate carbon loading amount. The time-dependent study indicates that the formation process of hierarchical MgAPO-11 obeys a reversed crystal growth route: crystallization started on the outer surface of the amorphous precursor, then extended to inward, and finally hierarchical molecular sieves assembled by nanosized crystals with a size of about 50 nm were obtained. The catalyst based on hierarchical MgAPO-11 exhibits a significant higher activity and selectivity than the conventional Pt/MgAPO-11 catalyst in the hydroisomerization of n -dodecane, attributing to its higher acidity and excellent diffusion properties resulting from the hierarchical pore architecture. [ABSTRACT FROM AUTHOR]

Ligand concentration dependent structural diversity and inter-conversion of hydrothermally synthesized metal carboxylate compounds, {[Mg(H 2 O) 6 ][Cu(pdc) 2 ]·2H 2 O} n ( 1 ), {[CuMg(pdc) 2 (H 2 O) 4 ]·2H 2 O} n ( 2 ), {2(Him)·[Cu(pdc) 2 ]} n ( 3 ), and {[Cu(pdc)(im) 2 ]·2H 2 O} n ( 4 ) (H 2 Pdc = pyridine-2,5-dicarboxylic acid and im = imidazole), have been thoroughly investigated. Formation of compounds 1 – 4 depends on the concentration of imidazole. Structure of all four compounds has been verified by single crystal X-ray diffraction and other physicochemical studies. Compound 3 catalyzes olefin epoxidation reaction in heterogeneous condition. [ABSTRACT FROM AUTHOR]

In this study, spinel magnesium cobalt ferrite (Co x Mg 1−x Fe 2 O 4 : x  = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) nanocomposites were synthesized successfully by modified sol-gel combustion method. Magnesium nitrate, cobalt nitrate and iron nitrate were used as the source of divalent (Mg 2+ and Co 2+ ) and trivalent (Fe 3+ ) cations, respectively and urea were used as the reducing (fuel) agent. The effects of cobalt ions on morphology, structural, optical, magnetic and photo-catalytic properties of spinel Co x Mg 1−x Fe 2 O 4 nanocomposites were investigated. Various characterization methods, including X-ray powder diffraction (XRD), high resolution scanning electron microscope (HR-SEM), transmission electron microscopy (HR-TEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transforms infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM) and photo-catalytic degradation (PCD) activity were used to study the phase purity, microstructure, particle size, elemental composition, functional group determination, band gap calculation, magnetic properties and degradation efficiency of nanoparticles, respectively. The observed results showed that the final products consists cubic spinel phase with sphere-like nanoparticles morphologies. Furthermore, spinel Co 0.6 Mg 0.4 Fe 2 O 4 nanocomposite showed highest PCD efficiency (98.55%) than other composition of ferrite nanoparticles. [ABSTRACT FROM AUTHOR]

MgAl 2 O 4 ‒W and MgAl 2 O 4 ‒W‒W 2 B composite powders were obtained rapidly in a single step by self-propagating high-temperature synthesis of WO 3 ‒Mg‒ x Al 2 O 3 and WO 3 ‒B 2 O 3 ‒Mg‒ y Al 2 O 3 systems. The addition of various Al 2 O 3 contents ( x and y -values) to the starting materials was considered as the main synthesis parameter. Thermodynamic calculations revealed that the adiabatic temperature of both systems was decreased with increasing Al 2 O 3 content. The XRD results indicated that after acid leaching of the WO 3 ‒Mg‒ x Al 2 O 3 combustion products, W and MgAl 2 O 4 were formed as the main phases and WO 2 , MgWO 4 and Al 2 O 3 as the minor constituents in the final composite. On the other hand, MgAl 2 O 4 ‒W composites were synthesized in the WO 3 ‒B 2 O 3 ‒Mg‒ y Al 2 O 3 system at y <1.4 mol. By increasing the y -value to 2.1 mol, W 2 B was formed as a new product leading to production of MgAl 2 O 4 ‒W‒W 2 B composite. The formation of spinel was confirmed by the Fourier transformed infrared spectroscopy analysis. Microstructure observations represented the uniform distribution of MgAl 2 O 4 blocks within the fine spherical W particles. The melting of Al 2 O 3 was found as a vital step for rapid synthesis of MgAl 2 O 3 by the SHS route. Finally, the possible formation mechanism of MgAl 2 O 4 during the combustion synthesis was proposed. [ABSTRACT FROM AUTHOR]

Mg60Zn35Ca5 amorphous powder alloys were synthesized by mechanical alloying (MA) technique. The results of the influence of high-energy ball-milling time on amorphization of the Mg60Zn35Ca5 elemental blend (intended for biomedical application) were presented in the study. The amorphization process was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). Initial elemental powders were mechanically alloyed in a Spex 8000 high-energy ball mill at different milling times (from 3 to 24 h). Observation of the powder morphology after various stages of milling leads to the conclusion that with the increase of the milling time the size of the powder particles as well as the degree of aggregation change. The partially amorphous powders were obtained in the Mg60Zn35Ca5 alloy after milling for 13-18h. The results indicate that this technique is a powerful process for preparing Mg60Zn35Ca5 alloys with amorphous and nanocrystalline structure. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles of multi-metal co-doped magnesium ferrite (MgFe 2 O 4 ) were synthesized from saprolite laterite ore by a hydrothermal method, and firstly proposed as a heterogeneous photon-Fenton-like catalyst for degradation of Rhodamine B (RhB). The factors that influence the degradation reaction including pH value, the concentration of H 2 O 2 and the amount of catalyst, were systematically investigated. The doped MgFe 2 O 4 exhibited a degradation efficiency up to 96.8%, and the chemical oxygen demand (COD) and total organic carbon (TOC) removal efficiencies about 85.6% and 68.3%, respectively, under visible light illumination for 180 min. The high activity is mainly attributed to the high specific surface area of the catalyst and the synergistic interaction between photo-catalytic oxidation and Fenton-like oxidation. Moreover, the catalyst also showed good stability and recycling performance for degrading RhB. After five consecutive degradation cycles, the activity decayed no more than 10%. Compared to other catalysts prepared from pure chemical agents, the multi-metal co-doped MgFe 2 O 4 is more competitive due to its high activity, good stability, ease of recollection, and especially the use of saprolite laterite ore as precursor. This work may provide a new avenue to synthesize efficient ferrite catalysts for degrading organic pollutants in wastewater by using natural minerals. [ABSTRACT FROM AUTHOR]

5-Membered ring heterocycles were α-lithiated or α-magnesiated so that they attacked SOCl2 or SO(OMe)2 forming symmetric - i.e. prochiral - diheteroaryl sulfoxides. The latter were treated with a 0.5- or 1.2-fold molar amount of 5:4 mixtures of dilithium (S)-BINOLate and diisobutylmagnesium. This allowed five asymmetric sulfoxide/magnesium exchange reactions to occur. They delivered asymmetric sulfoxides in up to 77 % yield and with up to 88 % ee. Surprisingly, four related diheteroaryl sulfoxides, bis(2-pyridyl) sulfoxide, and bis(3-pyridyl) sulfoxide were unamenable to such exchanges and decomposed instead. [ABSTRACT FROM AUTHOR]

Phase relations in the system Mg2SiO4-MgCr2O4 were studied at 10-24 GPa and 1600 °C using a high-pressure Kawai-type multi-anvil apparatus. We investigated the full range of starting compositions for the forsterite-magnesiochromite system to derive a P-X phase diagram and synthesize chromium-bearing phases, such as garnet, wadsleyite, ringwoodite, and bridgmanite of a wide compositional range. Samples synthesized at 10 GPa contain olivine with small chromium content and magnesiochromite. Mg2SiO4 wadsleyite is characterized by the pressure-dependent higher chromium solubility (up to 7.4 wt% Cr2O3). The maximal solubility of chromium in ringwoodite in the studied system (~18.5 wt% Cr2O3) was detected at P = 23 GPa, which is close to the upper boundary of the ringwoodite stability. Addition of chromium to the system moves the boundaries of olivine/wadsleyite and wadsleyite/ringwoodite phase transformations to lower pressures. Our experiments simulate Cr-rich phase assemblages found as inclusions in diamonds, mantle xenoliths, and UHP podiform chromitites. [ABSTRACT FROM AUTHOR]

Low-frequency current noise measurements were performed on Mg-doped ZnO (MZO) nanorod photodetectors (PD), and 1/f noise was observed in both dark and under ultraviolet (UV) illumination. Results show that the average length and diameter of the nanorods were 609 nm and approximately 50 nm, respectively. The X-ray diffraction spectrum showed that the Mg-doped ZnO nanorods had a wurtzite hexagonal sturcture. The photoelectric properties of the nanorods were stable under UV illumination. The resulting Mg-doped ZnO nanorods had excellent potential for UV photodetector applications. Mg-doped ZnO nanorod UV photodetectors had a high UV-to-visible ratio and a fast rise/fall time. The dynamic response of the Mg-doped ZnO nanorod photodetector was stable and reproducible with an on/off current contrast ratio of approximately 4 × 10 3 . The UV-to-visible rejection ratio of the sample was approximately 400 when biased at 1 V, and the fabricated UV photodetector was visible-blind with a sharp cutoff at 350 nm. The low-frequency noise spectra obtained from the UV photodetector were caused by the 1/f noise. The noise-equivalent power (NEP) and normalized detectivity (D * ) of the Mg-doped ZnO nanorod PD were 3.35 × 10 −10 W and 1.49 × 10 8 cm Hz0.5 W −1 , respectively. Under UV illumination, the NEP and D * were 1.8 × 10 −6 W and 2.7 × 106 cm Hz0.5 W −1 , respectively. [ABSTRACT FROM AUTHOR]

Lime addition as well as formation of struvite through the addition of magnesium and phosphorus salts provide good pH buffering and may reduce odour emission. This study investigated the odour emission during food waste composting under the influence of lime addition, and struvite formation. Composting was performed in 20-L reactors for 56 days using artificial food waste mixed with sawdust at 1.2:1 (w/w dry basis). VFA was one of the most important odours during food waste composting. However, during thermophilic phase, ammonia is responsible for max odour index in the exhaust gas. Trapping ammonia through struvite formation significantly reduced the maximum odour unit of ammonia from 3.0 × 10 4 to 1.8 × 10 4 . The generation and accumulation of acetic acid and butyric acid led to the acidic conditions. The addition of phosphate salts in treatment with struvite formation improved the variation of total bacteria, which in turn increased the organic decomposition. [ABSTRACT FROM AUTHOR]

Nickel sulfides decorated reduced graphene oxide (rGO) has been produced by co-reducing Ni 2+ and graphene oxide (GO), and is subsequently ball milled with Mg nanoparticles (NPs) produced by hydrogen plasma metal reaction (HPMR). The nickel sulfides of about 800 nm completely in situ change to MgS, Mg 2 Ni and Ni multiple catalysts after first hydrogenation/dehydrogenation process at 673 K. The Mg-5wt%NiS/rGO nanocomposite shows the highest hydrogen desorption kinetics and capacity properties, and the catalytic effect order of the additives is NiS/rGO, NiS and rGO. At 573 K, the Mg-NiS/rGO nanocomposite can quickly desorb 3.7 wt% H 2 in 10 min and 4.5 wt% H 2 in 60 min. The apparent hydrogen absorption and desorption activation energies of the Mg-5wt%NiS/rGO nanocomposite are decreased to 44.47 and 63.02 kJ mol −1 , smaller than those of the Mg-5wt%rGO and Mg-5wt%NiS samples. The best hydrogen desorption properties of the Mg-5wt%NiS/rGO nanocomposite can be explained by the synergistic catalytic effects of the highly dispersed MgS, Mg 2 Ni and Ni catalysts on the rGO sheets, and the more nucleation sites between the catalysts, rGO sheets and Mg matrix. [ABSTRACT FROM AUTHOR]

Embedded Si/graphene composite was fabricated by a novel method, which was in situ generated SiO particles on graphene sheets followed by magnesium-thermal reduction. The tetraethyl orthosilicate (TEOS) and flake graphite was used as original materials. On the one hand, the unique structure of as-obtained composite accommodated the large volume change to some extent. Simultaneously, it enhanced electronic conductivity during Li-ion insertion/extraction. The MR-Si/G composite is used as the anode material for lithium ion batteries, which shows high reversible capacity and ascendant cycling stability reach to 950 mAh·g at a current density of 50 mA·g after 60 cycles. These may be conducive to the further advancement of Si-based composite anode design. [ABSTRACT FROM AUTHOR]

Magnesium ferrite was doped with Nd to get MgFeNd O ( x = 0 to 0.04). The samples were synthesized by a without water and surfactant (WOWS) sol-gel technique, and pellets were sintered at different temperatures. An inverse spinel structure was confirmed by the X-ray diffraction (XRD) pattern. Lattice constants increased with the increase in Nd doping. Microstructure analysis by SEM shows that particles are spherical in shape. AC electrical properties were studied at room temperature in the frequency range of 20 Hz-3 MHz. A minimum dielectric loss tangent value was achieved with x = 0.02 concentration of Nd, and it is suitable for high-frequency applications. [ABSTRACT FROM AUTHOR]

In this work, magnesium ferrite (MgFe 2 O 4 )/biochar magnetic composites (MFB-MCs) were prepared and utilized to remove phosphate from aqueous solutions. MFB-MCs were synthesized via co-precipitation of Fe and Mg ions onto a precursor, followed by pyrolysis. Characterization results confirmed that MgFe 2 O 4 nanoparticles with a cubic spinel structure were successfully embedded in the biochar matrix, and this offered magnetic separability with superparamagnetic behavior and enabled higher phosphate adsorption performance than that of pristine biochar and sole MgFe 2 O 4 nanoparticles. Batch experiments indicated that phosphate adsorption on the MFB-MCs is highly dependent on the pH, initial phosphate concentration, and temperature, while it was less affected by ionic strength. Analysis of activation and thermodynamic parameters as well as the isosteric heat of adsorption demonstrated that the phosphate adsorption is an endothermic and physisorption process. Lastly, highly efficient recyclability of the MFB-MCs suggested that they are a promising adsorbent for phosphate removal from wastewater. [ABSTRACT FROM AUTHOR]

Recently, magnesium and its alloys have attracted great attention for use as biomaterial due to their good mechanical properties and biodegradability in the bio environment. In the present work, nanocomposites of Mg - 5Zn - 0.3Ca/nHA were prepared using a powder metallurgy method. The powder of Mg, Zn and Ca were firstly blended, then four different mixtures of powders were prepared by adding nHA in different percentages of 0, 1, 2.5 and 5%wt. Each mixture of powder separately was fast milled, pressed, and sintered. Then, the microstructure and mechanical properties of the fabricated nanocomposites were investigated. The XRD profile for nanocomposites showed that the intermetallic phases of MgZn2, MgZn5.31 and Mg2Ca were created after sintering and the SEM micrographs showed that the grain size of nanocomposite reduced by adding the nHA. The nano composite with 1wt.% nHA increased the density of Mg alloy from 1.73 g/cm³ to 1. 75 g/cm³ by filling the pores at the grain boundaries. The compressive strength of Mg alloy increased from 295MPa to 322, 329 and 318MPa by addition of 1, 2.5 and 5wt.% nHA, respectively. [ABSTRACT FROM AUTHOR]

Optical glass was very important for the development of optical fiber sensor. In this paper, a new type fluoride glass of ZrF4-BaF2-AlF3-NaF-MgF2(ZBANM) was synthesized for sensing application which has low loss and high magneto-optical coefficient, and it was found that the glass system had at least 60% transmittance from 3.5 μm to 7 μm and smallest verdet constant of 4.628E −5 /(rad A −1 ) at 632.8 nm. The relationship among the compositions of sample glass with its thermal property, optical absorptivity and magnetic-optical coefficients was respectively studied with Thermal Gravimetric-Differential Thermal Analyzer, Fourier Transform infrared spectroscopy and a home-made magneto optical bench. The study indicated that transmittance of fluoride glass structure had been obviously improved after moderate content of Mg2+ and Na+ was doped. Simultaneously, with the molar ratio of alkaline-earth ions Mg increased, the Verdet constant of fluoride glass was increased. And the glass structure with composition of 48%ZrF4-24%BaF2-6%AlF3-8%NaF-14%MgF2 exhibited a small molar absorptivity and the largest Verdet constant of 2.853E −4 /(rad A −1 ). [ABSTRACT FROM AUTHOR]

The tris[(1-isopropylbenzimidazol-2-yl)-dimethylsilyl)]methyl ligand, [TismPriBenz], has been employed to form the magnesium carbatrane compound, [TismPriBenz]MgH, which possesses a terminal hydride ligand. Specifically, [TismPriBenz]MgH is obtained via the reaction of [TismPriBenz]MgMe with PhSiH3. The reactivity of [TismPriBenz]MgMe and [TismPriBenz]MgH allows access to a variety of other structurally characterized carbatrane derivatives, including [TismPriBenz]MgX [X = F, Cl, Br, I, SH, N(H)Ph, CH(Me)Ph, O2CMe, S2CMe]. In addition, [TismPriBenz]MgH is a catalyst for (i) hydrosilylation and hydroboration of styrene to afford the Markovnikov products, Ph(Me)C(H)SiH2Ph and Ph(Me)C(H)Bpin, and (ii) hydroboration of carbodiimides and pyridine to form N-boryl formamidines and N-boryl 1,4- and 1,2-dihydropyridines, respectively. [ABSTRACT FROM AUTHOR]

The separation behaviors of Mg2+ and Li+ were investigated using molecular dynamics. Two functionalized graphene nanopore models (i.e., co_5 and coo_5) inspired by the characteristic structural features of Mg2+ channels were used. Both nanopores exhibited a higher preference to Mg2+ than to Li+, and the selectivity ratios were higher for coo_5 than for co_5 under all the studied transmembrane voltages. An evaluation of the effect of coordination on the ionic hydration microstructures for both nanopores showed that the positioning of the modified groups could better fit a hydrated Mg2+ than a hydrated Li+, as if Mg2+ was not dehydrated according to hydrogen bond analysis of the ionic hydration shells. This condition led to a lower resistance for Mg2+ than for Li+ when traveling through the nanopores. Moreover, a distinct increase in hydrogen bonds occurred with coo_5 compared with co_5 for hydrated Li+, which made it more difficult for Li+ to pass through coo_5. Thus, a higher Mg2+/Li+ selectivity was found in for coo_5 than for co_5. These findings provide some design principles for developing artificial Mg2+ channels, which have potential applications as Mg2+ sensors and novel devices for Mg2+/Li+ separation. [ABSTRACT FROM AUTHOR]

In the present study, Young's modulus measurements and indirect cytotoxicity test were performed on Mg (0.97, 1.98, 2.5) vol% TiO 2 , Mg (0.58, 0.97, 1.98) vol% TiC, and Mg (0.58, 0.97, 1.98) vol% TiN, synthesized using the Disintegrated Melt Deposition technique to determine the cytotoxicity of low volume nano-particulate reinforcement on magnesium. The results of the indirect MTT assay on Day 3 and Day 5 indicate that 2.5 vol% TiO 2 , TiC and TiN has little effect on the cytotoxicity when added as low volume fraction reinforcement to magnesium. While (0.97, 1.98) vol% TiO 2 negatively affected the cytotoxicity when added to Mg. The Young's modulus of the materials was found to remain close to that of cortical bone which would suggest that the stress shielding effect would be reduced as the increase in Young's modulus was mitigated by the low volume addition of reinforcements. [ABSTRACT FROM AUTHOR]

New structural, spectroscopic and thermal data on the formation and characterization of solid solutions containing cobalt blödite, Na2Co(SO4)2⋅4H2O, and magnesium blödite, Na2Mg(SO4)2⋅4H2O, are provided in this contribution. On the basis of the solubility data and X-ray powder diffraction it is found that both compounds form a continuous series of solid solutions due to their isostructureness. It is established that the lattice parameters of the solid solutions obey the Vegard rule. The infrared spectra of the blödite phases are interpreted in the light of their crystal structures. The strength of the hydrogen bonds in both hydrates and in the solid solutions is analyzed in terms of matrix infrared spectroscopy (matrix-isolated HDO molecules). The thermal behavior and phase transitions of the solid phases are studied by TG and DTA analyses. It is found that the dehydration processes occur stepwise forming thus intermediate hydrates and anhydrous compounds at 350°C. [ABSTRACT FROM AUTHOR]

Magnesium-silica-hydrates (M-S-H) is a promising binder for magnesia castables due to its bonding strength and progressive dehydration behavior over a wide temperature range during the heating-up stage. Sodium metasilicate and caustic magnesia were used to form M-S-H in magnesia castables. The results showed that M-S-H was remarkably produced in the caustic magnesia-microsilica slurries containing sodium metasilicate with increasing pH value, which activated the hydrolysis of microsilica into silicic ions and enhanced the M-S-H formation. When 0.3 wt% caustic magnesia and 0.05 wt% sodium metasilicate as additives were incorporated into magnesia castables, the cold crushing strength and cold modulus of rupture of castables after drying at 110 °C reached the maximum value of 68.3 MPa, which corresponded to ~ 40% improvement in comparison with those of caustic magnesia and sodium metasilicate-free magnesia castables. Besides, the enhanced formation of M-S-H bonding system contributed to a better explosion resistance of magnesia castables. [ABSTRACT FROM AUTHOR]

Crystallization experiments were performed at high supersaturation to obtain metastable (Mg,Fe)CO3 precipitates and study their evolution during hydrothermal heating in a nitrogen atmosphere. The primary (Mg,Fe)CO3 solids undergo a dissolution-recrystallization process driven by two forces: the preferential partition of Fe2+ toward the (Mg,Fe)CO3 solid solution and the oxidation of aqueous Fe2+ species to form Fe(III)-bearing solids. Under limited oxygen supply, the oxidation of Fe2+ is a slow process, particularly in the presence of chlorine and inorganic carbon. In absence of oxidation, the initial solid solution should become increasingly Fe-rich as the supersaturation decreases and the system approaches equilibrium. Here, the secondary (Mg,Fe)CO3 solids become the wrong way round, Mg-rich. The gradual oxidation of the aqueous Fe2+ species eventually leads to precipitation of magnetite, which is also metastable because the aqueous solution is maximally supersaturated with respect to hematite. In most computer implementations, the aqueous activities of Fe2+ and Fe3+ are adjusted to redox equilibrium, and the supersaturation with respect to Fe-bearing solids is determined from these activities. Unfortunately, this approach does not provide supersaturation values in "real time". Reactions between aqueous species are actually not instantaneous and can be slower than the dissolution/precipitation of related solids. Considering this fact is essential in modeling the artificial carbonation of ferromagnesian minerals for CO2 sequestration purposes. [ABSTRACT FROM AUTHOR]

By an easy co-precipitation method, the magnetic magnesium-aluminum-lanthanum composite was successfully synthesized. The effects of the synthetic conditions such as Mg/Al/La molar ratio and calcination temperature on fluoride removal by the adsorbent were studied. The adsorbents were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and energy-dispersive X-ray spectroscopy (EDS). By means of changing various conditions, such as contact time, solution pH, initial fluoride concentration, temperature and coexisting anions, batch adsorption studies were worked out. Results indicated that with a Mg/Al/La molar ratio of 16:1:1, at 500 °C, near neutral pH and room temperature, the adsorbent obtained the maximum capacity of 65.75 mg/g for fluoride adsorption. The adsorption process was fitted well with the Langmuir isotherm model and the pseudo-first order kinetic model. Adsorption mechanism involved electrostatic interaction on surface and ion exchange interaction. All results indicated that the magnetic magnesium-aluminum-lanthanum composite can be a very promising adsorbent, has potential application in fluoride removal in water treatment and has positive effects on human health. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A new magnesium phosphate, Na3RbMg7(PO4)6 [trisodium rubidium heptamagnesium hexakis(orthophosphate)], has been synthesized as single crystals by the flux method and exhibits a new structure type. Its original structure is built up from MgOx(x = 5 and 6) polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetrahedra. 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 interstitial cavities. [ABSTRACT FROM AUTHOR]

A new magnesium phosphate, Na3RbMg7(PO4)6 [trisodium rubidium heptamagnesium hexakis(orthophosphate)], has been synthesized as single crystals by the flux method and exhibits a new structure type. Its original structure is built up from MgOx(x = 5 and 6) polyhedra linked directly to each other through common corners or edges and reinforced by corner-sharing with PO4 tetrahedra. 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 interstitial cavities. [ABSTRACT FROM AUTHOR]

Both MgSi and MgSn compounds were synthesized by an ultra-fast self-propagating high-temperature synthesis (SHS) method. The data regarding SHS were obtained via theoretical calculation combined with experiments, showing that the adiabatic temperature T and ignition temperature T of MgSi are a little higher than those of MgSn. The mechanism of phase evolution and the concomitant microstructure evolution during the synthesis process of MgSi and MgSn compounds were investigated by adopting SHS technique coupled with a sudden quenching treatment. Differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and x-ray powder diffraction (XRD) results indicate that MgSi compound can be directly synthesized through the reaction of Mg and Si elements at around 850 K. Correspondingly, the formation of MgSn needs to undergo melting of Sn and the subsequent feeble reaction between Mg and Sn elements before the large scale transformation at 730 K. As the groundwork, this research embodies great significance for future study on the ultrafast SHS process of the ternary MgSiSn solid solutions. [ABSTRACT FROM AUTHOR]

Nitridosilicates represent an intriguing class of materials and are typically made up of highly condensed tetrahedral network structures. Alkaline-earth nitridosilicates emerged as unique host materials for Eu2+ doped luminophores which found broad application in phosphor-converted (pc)-LEDs. In contrast to common strategies of preparing nitridosilicates by bottom-up syntheses, we have now succeeded to post-synthetically design nitridosilicates by ion exchange in metal halide melts. We describe the syntheses of hitherto unknown but predicted alkaline-earth nitridosilicates, Mg2Si5N8 and β-Ca2Si5N8. Both compounds were obtained by ion exchange starting from pre-synthesized nitridosilicates. In situ investigations of the ion-exchange process show that the Si-N network topology remains preserved. Therefore the reaction offers a significant increase of synthetic control with respect to classical bottom-up syntheses. [ABSTRACT FROM AUTHOR]

Nitridosilicates represent an intriguing class of materials and are typically made up of highly condensed tetrahedral network structures. Alkaline-earth nitridosilicates emerged as unique host materials for Eu2+ doped luminophores which found broad application in phosphor-converted (pc)-LEDs. In contrast to common strategies of preparing nitridosilicates by bottom-up syntheses, we have now succeeded to post-synthetically design nitridosilicates by ion exchange in metal halide melts. We describe the syntheses of hitherto unknown but predicted alkaline-earth nitridosilicates, Mg2Si5N8 and β-Ca2Si5N8. Both compounds were obtained by ion exchange starting from pre-synthesized nitridosilicates. In situ investigations of the ion-exchange process show that the Si-N network topology remains preserved. Therefore the reaction offers a significant increase of synthetic control with respect to classical bottom-up syntheses. [ABSTRACT FROM AUTHOR]

Magnesium (Mg) is successfully synthesized from the direct reduction of dibutylmagnesium (MgBu2) with calcium (Ca). By adding 1-dodecanethiol, the morphology of the magnesium particles is controlled and magnesium nanofibers with a length of 0.4-4 µm and a width of 40 nm are obtained. Besides magnesium nanofibers, isolated irregular shaped calcium particles are also observed as a by-product of the reaction. The nanofibers readily absorbed hydrogen at 300 °C and hydrogen release occurred at much lower temperatures (360 °C) compared to the equivalent bulk material. More remarkably, these nanofibers remain stable during hydrogen cycling, but they partially react with the remaining calcium to form the ternary hydride phase Ca19Mg8H54-a phase that is usually obtained at high temperatures >500 °C and hydrogen pressure 2500 MPa. Hydrogen absorption within these magnesium nanofibers shows a slightly lower enthalpy as compared to bulk magnesium. However, the hydrogen desorption properties are influenced by the presence of calcium and its reaction with magnesium. [ABSTRACT FROM AUTHOR]

Mesoporous MgAl2O4 powder with a high surface area (226 m2 g−1) is synthesized by a co-precipitation method in the presence of a capping agent. The obtained powder was employed to prepare catalysts ( y Ni/MA) with different nickel contents ( y=3.5, 7, 10.5, and 14 wt %). The catalysts were characterized by BET, XRD, H2-TPR, TPD, TPO, and SEM techniques to study the effect of support and nickel content on the surface properties, Ni-MgAl2O4 interactions, Ni2+ species, nickel particle size, and reducibility. The catalytic performance of the y Ni/MgAl2O4 catalysts was tested in the steam prereforming of natural gas in the range of 400-550 °C, atmospheric pressure, low steam to carbon molar ratio ( S/ C=1.5) and a high gas hourly space velocity (GHSV=1×105 mL g−1catalyst h−1). The 10.5 % Ni/MA catalyst showed the highest nickel metal area (2.91 m2 g−1catalyst) which resulted in around 100 % of ethane and propane conversions at temperatures higher than 500 °C. This catalyst exhibited a high stability during 50 h time on-stream, implying a high resistance to coke formation. While the 10.5 % Ni/MAC catalyst, the support (MAC) of which was synthesized by the solid-state reaction method, demonstrated the lowest nickel area (0.04 m2 g−1catalyst) and a poor catalytic performance with a plenty of carbon deposition during steam prereforming reaction. [ABSTRACT FROM AUTHOR]

Glycine (Gly)-doped and Cu-and-Gly-co-doped MgB samples were two-step synthesized by a short 800 °C period followed by sintering at 600 °C for 2 h. In view of the depression of oxidation and the significant reduction of the synthesis time, the sintering efficiency was improved due to the instantaneous high-temperature process, in contrast with the one-step sintered samples at 800 °C. The critical current density was examined to be 5.1 × 10 and 8.4 × 10 A cm at 20 K and 3 T for the Gly-doped and the co-doped samples, respectively. Such enhancement, with respect to the one-step sintered un-doped sample, is attributed to the fine MgO (~20 nm) and MgCu (~10 nm) pinning centers. The MgO and MgCu in the co-doped sample precipitated at the grain boundary and within the grains, respectively. Besides, the residual Mg phase in the Gly-doped sample remained on the surface of the MgB grains, which proved the screw-dislocation growth of the MgB grains, i.e. the grains extended from inner center to outer zone at low temperature. [ABSTRACT FROM AUTHOR]

The reactions between magnesium or zinc alkyls and 1,8-bis(triorganosilyl)diaminonaphthalenes afford the 1,8-bis(triorganosilyl)diamidonaphthalene complexes with elimination of alkanes. The reaction between 1,8-C10H6(NSiMePh2H)2 and one or two equivalents of MgnBu2 affords two complexes with differing coordination environments for the magnesium; the reaction between 1,8-C10H6(NSiMePh2H)2 and MgnBu2 in a 1 : 1 ratio affords 1,8-C10H6(NSiMePh2)2{Mg(THF)2} (1), which features a single magnesium centre bridging both ligand nitrogen donors, whilst treatment of 1,8-C10H6(NSiR3H)2 (R3 = MePh2, iPr3) with two equivalents of MgnBu2 affords the bimetallic complexes 1,8-C10H6(NSiR3)2{nBuMg(THF)}2 (R3 = MePh22, R3 = iPr33), which feature four-membered Mg2N2 rings. Similarly, 1,8-C10H6(NSiiPr3)2{MeMg(THF)}2 (4) and 1,8-C10H6(NSiMePh2)2{ZnMe}2 (5) are formed through reactions with the proligands and two equivalents of MMe2 (M = Mg, Zn). The reaction between 1,8-C10H6(NSiMePh2H)2 and two equivalents of MeMgX affords the bimetallic complexes 1,8-C10H6(NSiMePh2)2(XMgOEt2)2 (X = Br 6; X = I 7). Very small amounts of [1,8-C10H6(NSiMePh2)2{IMg(OEt2)}]2 (8), formed through the coupling of two diamidonaphthalene ligands at the 4-position with concomitant dearomatisation of one of the naphthyl arene rings, were also isolated from a solution of 7. [ABSTRACT FROM AUTHOR]

The quaternary nitrides Ca4Mg5Ge3N10 and Sr2Mg3GaN4.33 were synthesized by employing the Na azide route in weld-shut Ta ampules. The two compounds are homotypic and crystallize in the monoclinic space group C2/m (no. 12). The crystal structures were solved and refined on the basis of single-crystal X-ray diffraction data [Ca4Mg5Ge3N10: a = 11.269(3), β = 3.3267(11), c = 8.008(3) Å, β = 109.80(2)°, V = 282.44(16) Å3, Z = 1; Sr2Mg3GaN4.33: a = 11.737(2), β = 3.4610(7), c = 7.8610(16) Å, β = 108.03(3)°, V = 303.65(12) Å3, Z = 1]. The three-periodic anionic substructures of both nitrides are made up of MN4 tetrahedra with mixed occupation of central atoms M = Mg/Ge and Mg/Ga, respectively. Corner- and edge-sharing of MN4 tetrahedra results in vierer and sechser ring channels along [010]. Alkaline earth metal ions are located within sechser ring channels. The crystal structures are also homeotypic with that of known Ca4Mg5Ge3N10 and represent a more highly condensed variant of the MII 2Si5N8 (MII = Sr, Ba) type of structure. [ABSTRACT FROM AUTHOR]

The quaternary nitrides Ca4Mg5Ge3N10 and Sr2Mg3GaN4.33 were synthesized by employing the Na azide route in weld-shut Ta ampules. The two compounds are homotypic and crystallize in the monoclinic space group C2/m (no. 12). The crystal structures were solved and refined on the basis of single-crystal X-ray diffraction data [Ca4Mg5Ge3N10: a = 11.269(3), β = 3.3267(11), c = 8.008(3) Å, β = 109.80(2)°, V = 282.44(16) Å3, Z = 1; Sr2Mg3GaN4.33: a = 11.737(2), β = 3.4610(7), c = 7.8610(16) Å, β = 108.03(3)°, V = 303.65(12) Å3, Z = 1]. The three-periodic anionic substructures of both nitrides are made up of MN4 tetrahedra with mixed occupation of central atoms M = Mg/Ge and Mg/Ga, respectively. Corner- and edge-sharing of MN4 tetrahedra results in vierer and sechser ring channels along [010]. Alkaline earth metal ions are located within sechser ring channels. The crystal structures are also homeotypic with that of known Ca4Mg5Ge3N10 and represent a more highly condensed variant of the MII 2Si5N8 (MII = Sr, Ba) type of structure. [ABSTRACT FROM AUTHOR]