Au System Research Articles

The influence changing of Nuclear Potential on Quasi-Elastic Scattering in 16O+160Gd and 12C+197Au Systems

In this research, the effect of changing the potential depth V0 on the Quasi-elastic scattering and barrier distribution calculations have been studied using Wood-Saxon (WS) potential for 16O+160Gd and 12C+197Au systems. The chi square (χ2) is applied to compare the best fitted value of the diffuseness parameter between the theoretical calculations and the experimental data. The diffuseness parameter which used in this work is to be at standard value 0.63. The χ2 was applied to most suitable the better fitted value of the potential depth V0. According to the results, we noticed that some systems achieved a good match between the theoretical calculations and experimental data of Quasi-elastic scattering (dσqel/dσR) and the distribution calculations at the standard value of the potential depth or at a value lower than the standard value and no match was achieved at a value greater than the standard value of the potential depth V0. We conclude that the values of quasi-elastic scattering values increase when the value of potential depth decreases.

Tunable Intrinsic Phonon Mode versus Anomalous Thermal Transport in Two-Dimensional Strongly Anharmonic Group IB Chalcogenides A2IBSe1/2Te1/2 (AIB = Cu, Ag, or Au).

Group IB chalcogenides, as promising thermoelectric materials, have ultralow thermal transport. Here, we propose a peculiar intrinsic B2 phonon mode that includes the in-plane rotational and stretching vibrations of metal atoms in two-dimensional A2IBSe1/2Te1/2 (AIB = Cu, Ag, or Au). The B2 mode is sensitive to the metal-atom mass, temperature, and strain for effectively tuning the lattice thermal conductivity. The in-plane stretching vibration leads to an unexpected increase in the lattice thermal conductivity from Cu to Ag and to Au systems, in contrast to Keyes' theory. The s(I) phase can be stabilized by the temperature-hardened B2 mode to reduce the lattice thermal conductivity, following the ∼T-0.59 instead of the traditional ∼T-1 trend. The s(II)-to-s(I) phase transition is driven by the strain-softened B2 mode to greatly enhance thermal transport via weakening the anharmonicity. Our work establishes the relationship of tunable intrinsic phonon mode versus thermal transport in two-dimensional group IB chalcogenides.

A dependence of binary and planetary system destruction on subtle variations in the substructure in young star-forming regions

ABSTRACT Simulations of the effects of stellar fly-bys on planetary systems in star-forming regions show a strong dependence on subtle variations in the initial spatial and kinematic substructure of the regions. For similar stellar densities, the more substructured star-forming regions disrupt up to a factor of 2 more planetary systems. We extend this work to look at the effects of substructure on stellar binary populations. We present N-body simulations of substructured, and non-substructured (smooth) star-forming regions in which we place different populations of stellar binaries. We find that for binary populations that are dominated by close (<100 au) systems, a higher proportion are destroyed in substructured regions. However, for wider systems (>100 au), a higher proportion are destroyed in smooth regions. The difference is likely due to the hard–soft or fast–slow boundary for binary destruction. Hard (fast/close) binaries are more likely to be destroyed in environments with a small velocity dispersion (kinematically substructured regions), whereas soft (slow/wide) binaries are more likely to be destroyed in environments with higher velocity dispersions (non-kinematically substructured regions). Due to the vast range of stellar binary semimajor axes in star-forming regions (10−2 to 104 au), these differences are small and hence unlikely to be observable. However, planetary systems have a much smaller initial semimajor axis range (likely ∼1–100 au for gas giants) and here the difference in the fraction of companions due to substructure could be observed if the star-forming regions that disrupt planetary systems formed with similar stellar densities.

Adsorption of Metal Atoms on SiC Monolayer

The electronic, magnetic, and optical behaviors of metals (M = Ag, Al, Au, Bi, Ca, Co, Cr, Cu, Fe, Ga, K, Li, Mn, Na, Ni) adsorbed on the SiC monolayer have been calculated based on density functional theory (DFT). The binding energy results show that all the M-adsorbed SiC systems are stable. All the M-adsorbed SiC systems are magnetic with magnetic moments of 1.00 μB (Ag), 1.00 μB (Al), 1.00 μB (Au), 1.01 μB (Bi), 1.95 μB (Ca), 1.00 μB (Co), 4.26 μB (Cr), 1.00 μB (Cu), 2.00 μB (Fe), 1.00 μB (Ga), 0.99 μB (K), 1.00 μB (Li), 3.00 μB (Mn), and 1.00 μB (Na), respectively, except for the Ni-adsorbed SiC system. The Ag, Al, Au, Cr, Cu, Fe, Ga, Mn, and Na-adsorbed SiC systems become magnetic semiconductors, while Bi, Ca, Co, K, and Li-adsorbed SiC systems become semimetals. The Bader charge results show that there is a charge transfer between the metal atom and the SiC monolayer. The work function of the K-adsorbed SiC system is 2.43 eV, which is 47.9% lower than that of pristine SiC and can be used in electron-emitter devices. The Bi, Ca, Ga, and Mn-adsorbed SiC systems show new absorption peaks in the visible light range. These results indicate that M-adsorbed SiC systems have potential applications in the field of spintronic devices and solar energy conversion photovoltaic devices.

Analytic procedure for the evaluation of copper intermetallic diffusion in electroplated gold coatings with energy dispersive X-ray microanalysis

A method for the determination of the intermetallic diffusion coefficient in the Cu–Au system is described based on energy dispersive X-ray techniques. XRF and EDS analysis were used to measure the thickness of the electroplated gold coating and the copper diffused through it, respectively. This information was used to obtain the diffusion coefficient through an equation based on Fick's law. Colour measurements and metallographic section analysis of the samples were also performed to evaluate alternative methods for a qualitative determination of diffusion rate. The thickness of the gold layer was chosen in agreement with what is used in decorative and functional applications (<1 μm). The measurements were performed on samples heated in a range of temperatures between 100 °C and 200 °C from 12 to 96 h. The results obtained follow a linear trend between the logarithm of the diffusion coefficient and the inverse of the temperature and are in line with the values found in the literature.

Origin of biotite-rich xenoliths in the Eocene Beiya porphyry: Implications for upper-crustal Au remobilization and formation of giant porphyry Au systems in a collisional setting

Origin of biotite-rich xenoliths in the Eocene Beiya porphyry: Implications for upper-crustal Au remobilization and formation of giant porphyry Au systems in a collisional setting

Auranofin Targeting the NDM-1 Beta-Lactamase: Computational Insights into the Electronic Configuration and Quasi-Tetrahedral Coordination of Gold Ions.

Recently, the well-characterized metallodrug auranofin has been demonstrated to restore the penicillin and cephalosporin sensitivity in resistant bacterial strains via the inhibition of the NDM-1 beta-lactamase, which is operated via the Zn/Au substitution in its bimetallic core. The resulting unusual tetrahedral coordination of the two ions was investigated via the density functional theory calculations. By assessing several charge and multiplicity schemes, coupled with on/off constraining the positions of the coordinating residues, it was demonstrated that the experimental X-ray structure of the gold-bound NDM-1 is consistent with either Au(I)-Au(I) or Au(II)-Au(II) bimetallic moieties. The presented results suggest that the most probable mechanism for the auranofin-based Zn/Au exchange in NDM-1 includes the early formation of the Au(I)-Au(I) system, superseded by oxidation yielding the Au(II)-Au(II) species bearing the highest resemblance to the X-ray structure.

COMPLEX FORMATION OF GOLD (I) WITH 2-METHYLIMIDAZOLE

The complex formation process of Au (I) with 2-methylimidazole was studied by potentiometric titration. When 2-methylimidazole is added to the [AuCl2]-/Au system, the potential gradually decreases without any jumps. The nonlinearity of the dependence of E on –lg[2MI] indicates the stepwise nature of the complex formation between [AuCl2]- and 2-methylimidazole. The general and thermodynamic stability constants of the complexes were determined in the temperature range of 278-318 K (at T=298 K, lgβ0[AuСl(Н2МИ)]+=13.84±0.03; lgβ10[Au2МИCl]=5.38±0.05; lgβ20[Au(2МИ)2]+=10.60±0.03). The reliability of the determination of the constants is proved by the satisfactory agreement between the experimentally found values of the potentials (Eex.) with theoretical ones (Etheor.). As the temperature increases, the stability of the complexes increases. A change in the ionic strength of the solution has little effect on the stability of the complexes. Comparison of the process of complexation of gold (I) and gold (III) with 2-methylimidazole shows that the stability of the complexes of trivalent gold is superior to similar complexes of gold (I). The thermodynamic functions of the complex formation reaction were calculated by the temperature coefficient method. In this case, the value of ΔrН0 was determined from the tangent of the slope of the direct dependence lgβ0=f(1/T), and the value of ΔrS0 was determined from the segment cut off by this straight line on the y-axis. The change in the isobaric-isothermal potential was calculated by the equation ΔrG0= ΔrН0-TΔrS0. The substitution of chloride ions for a 2MI molecule is accompanied by a positive change in ΔН, which has a negative contribution to the spontaneous course of reactions. For the [AuCl2]- - 2MI system, the number of particles participating in the reaction remains unchanged and the positive change in ΔS is most likely due to the release of water molecules from the hydration shell of the initial substances and reaction products.

Increased levels of nerve growth factor accompany oxidative load in recurrent pregnancy loss. Machine learning applied to FT-Raman spectra study.

The presented article is focused on developing and validating an efficient, credible, minimally invasive technique based on spectral signatures of blood serum samples in patients with diagnosed recurrent pregnancy loss (RPL) versus healthy individuals who were followed at the Gynecology department. A total of 120 participants, RPL disease (n = 60) and healthy individuals (n = 60), participated in the study. First, we investigated the effect of circulating nerve growth factor (NGF) in RPL and healthy groups. To show NGF's effect, we measured the level of oxidative loads such as Total Antioxidant Level (TAS), Total Oxidant Level (TOS), and Oxidative Stress Index (OSI) with Beckman Coulter AU system and biochemical assays. We find a correlation between oxidative load and NGF level. Oxidative load mainly causes structural changes in the blood. Therefore, we obtained Raman measurements of the participant's serum. Then we selected two Raman regions, 800 and 1800cm-1, and between 2700cm-1 and 3000cm-1, to see chemical changes. We noted that Raman spectra obtained for RPL and healthy women differed. The findings confirm that the imbalance between reactive oxygen species and antioxidants has important implications for the pathogenesis of RPL and that NGF levels accompany the level of oxidative load in the RPL state. Biomolecular structure and composition were determined using Raman spectroscopy and machine learning methods, and the correlation of these parameters was studied alongside machine learning technologies to advance toward clinical translation. Here we determined and validated the development of instrumentation for the Analysis of RPL patients' serum that can differentiate from control individuals with an accuracy of 100% using the Raman region corresponding to structural changes. Furthermore, this study found a correlation between traditional biochemical parameters and Raman data. This suggests that Raman spectroscopy is a sensitive tool for detecting biochemical changes in serum caused by RPL or other diseases.

Mechanistic understanding of the interfacial properties of metal-PtSe2 contacts.

With the advantages of a moderate band gap, high carrier mobility and good environmental stability, two-dimensional (2D) semiconductors show promising applications in next-generation electronics. However, the accustomed metal-2D semiconductor contact may lead to a strong Fermi level pinning (FLP) effect, which severely limits the practical performance of 2D electronics. Herein, the interfacial properties of the contacts between a promising 2D semiconductor, PtSe2, and a sequence of metal electrodes are systematically investigated. The strong interfacial interactions formed in all metal-PtSe2 contacts lead to chemical bonds and a significant interfacial dipole, resulting in a vertical Schottky barrier for Ag, Au, Pd and Pt-based systems and a lateral Schottky barrier for Al, Cu, Sc and Ti-based systems, with a strong FLP effect. Remarkably, the tunneling probability for most metal-PtSe2 is significantly high and the tunneling-specific resistivity is two orders of magnitude lower than that of the state-of-the-art contacts, demonstrating the high efficiency for electron injection from metals to PtSe2. Moreover, the introduction of h-BN as a buffer layer leads to a weakened FLP effect (S = 0.50) and the transformation into p-type Schottky contact for Pt-PtSe2 contacts. These results reveal the underlying mechanism of the interfacial properties of metal-PtSe2 contacts, which is useful for designing advanced 2D semiconductor-based electronics.

4H-SiC Ohmic contacts formation by MoS2 layer intercalation: A first-principles study

Due to the difficulty of forming a low Schottky barrier at the interface of a metal/SiC contact, preparing Ohmic contacts is still a key technical problem in developing SiC devices. In this paper, the effects of MoS2 intercalation on the interface properties of metal/SiC (Al, Ag, Ti, Au, and Mg) systems were investigated by first-principles calculation. The calculations show that all the metal/SiC contacts exhibit p-type Schottky contacts with strong Fermi level pinning (FLP) at the interfaces. After inserting a layer of MoS2, the Schottky barrier heights are significantly reduced. All the metal/MoS2/SiC systems are tuned to be n-type Ohmic contacts. By calculating and analyzing electron localization functions, projected band structure, partial density of states, and planar-averaged charge density difference, the Ohmic contact formation mechanism may be due to the saturation of dangling bonds of the SiC surface, the reduction in metal-induced gap states, the formation of interface dipole layer, and the shift of FLP position to the interface of metal/MoS2.

Systematic textural and geochemical variations in magnetite from a porphyry-skarn Cu (Au) system and implications for ore formation, perspective from Xinqiao Cu-Fe-Au deposit, eastern China

Magnetite is an abundant mineral in both porphyry ore and related skarn ore; the physical and chemical characteristics of magnetite in different parts of mineralized zones may allow determination of the related ore-forming processes. We present the results of detailed textural and chemical studies of magnetite from Xinqiao porphyry-skarn Cu-Au deposit, eastern China, to constrain the causative magmatic-hydrothermal processes.Five types of magnetite are identified, magmatic magnetite (type1) occurs in the causative quartz monzodiorite intrusion; re-equilibrated magmatic magnetite (type2) occurs in endoskarn; hydrothermal magnetite aggregated with hydrothermal biotite (type3a) or disseminated (type3b) and veins (type3c) occurs in the porphyry alteration zone; massive magnetite (type4) and disseminated or banded magnetite (type5) occurs in the exoskarn. Magmatic magnetite with oxy-exsolution of ilmenite lamellae indicates the magma was oxidized, and type1 magnetite that underwent hydrothermal re-equilibration (replaced by titanite and hematite) to form type2 magnetite indicates that the early magmatic-hydrothermal fluid was high temperature and highly oxidized during endoskarn formation. The Ti-rich type3a-c magnetite and the presence of ilmenite-rutile lamellae in type3c magnetite from the porphyry alteration zone demonstrate Ti mobility in the porphyry ore-forming fluid, which was high T (450 °C), oxidized and volatile-rich (hydrothermal fluorapatite; F > 3.0 wt%). Trace elements Ti, V, Sc, Co, Ni are positively correlated and decrease from type3 to type5; Mg, Mn, Zn increase in the same sequence, consistent with the temperature of fluid decreasing from porphyry to skarn mineralization, and increasing fluid-rock interaction. The elevated Sn in type5 magnetite and its coexistence with hematite in the retrograde skarn zone also indicate that the fluid remained oxidized during early skarn ore formation. Crystallization of magnetite increased the supply of reduced sulfur, which assisted formation of the Cu mineralization at Xinqiao. We highlight that magnetite textures and compositions can effectively trace the ore-forming processes in porphyry-skarn deposits, and show that porphyry related skarn magnetites are distinguishable from those in skarn Fe, skarn Cu, IOA (iron oxide-apatite) and porphyry deposits in the MLYB.

Investigation of simultaneous variation of surface diffuseness and central depression in the estimation of absorption effects

In this paper, we investigate the effect of simultaneous variation of surface diffuseness and central depression, in case of model-dependent Fermi matter density distributions, on the estimation of survival probability, Coulomb excitation cross-section and absorption effects for [Formula: see text] Au system. Further, the role of model-dependent Fermi matter density distribution and model independent [Formula: see text] matter density distribution has also been investigated in the estimation of the above-mentioned quantities. The simultaneous variation of the parameters of the model-dependent density distribution and choice of the density distribution are found to be affecting all the above-mentioned quantities significantly and hence plays a crucial role in the analysis of the Coulomb excitation experiments also.

MoCu bimetallic nanoalloy-modified copper molybdenum oxide with strong SPR properties; a 2D–0D system for enhanced degradation of antibiotics

2D copper molybdenum oxide-supported MoCu alloy nanoparticle photocatalysts are prepared via a facile hydrothermal and chemical reduction method. The MoCu nanocrystals with a size of less than 10 nm are formed through the reduction-alloying of metal ions and well dispersed on the surface of the copper molybdenum oxide nanoplates (CMO). The CMO/MoCu nanocomposite is shown to possess a 2D–0D structure, a z-scheme charge mobility pathway, and excellent photocatalytic performance in ciprofloxacin (CFX) and tetracycline (TC) degradation. The anchored MoCu alloy nanoparticles on the surface of CMO plates provide remarkable charge separation, large surface area, and numerous accessible active sites for producing reactive species. The 2D–0D CMO/MoCu composite showed the highest catalytic activity with the activation energy of – 0.640 and – 0.923 kJ mol−1 for CFX and TC, respectively. This research proposes a new strategy for the replacement of Pt, Au, and Ag-based photocatalytic systems with new nanoalloys of low-cost SPR metals.

Pyrite geochemistry in a porphyry-skarn Cu (Au) system and implications for ore formation and prospecting: Perspective from Xinqiao deposit, Eastern China

AbstractStratabound ore has been recognized as an end-member of porphyry copper systems, but pyrite chemistry has not been widely applied to linking stratabound ore with the related porphyry and skarn system. Stratabound ore is commonly developed around porphyry-skarn systems in eastern China, and is characterized by abundant colloform pyrite; however the origin of the colloform pyrite has been contentious. Xinqiao deposit is ideal for study of pyrite geology and geochemistry with the aim of elucidating formation of the stratabound ore and to decipher the evolution of pyrite compositions in a porphyry-skarn environment. The colloform pyrite paragenesis and S isotopes indicate that it formed during early skarn mineralization, based on its occurrence in stockwork veins cutting skarn minerals, and that it is replaced by later hypogene sulfides; the δ34S of colloform pyrite (average 6.12‰) is close to the δ34S value of both porphyry-(average 5.06‰) and skarn-type pyrite (average 4.65‰). The colloform texture formed as an aggregate of nanometer- or micrometer-sized (&amp;lt;0.2 µm) pyrite cubes produced by rapid crystallization from a high-fS2, low-temperature, and supersaturated fluid. Super-saturation of the fluid was probably produced by rapid decompression that triggered fluid boiling and cooling when the magmatic-hydrothermal fluid (derived from Cretaceous magma) flowed along the Devonian-Carboniferous unconformity. Subsequently, the colloform pyrite was replaced by later stage pyrite with distinctive trace elements (Co, Ni, and Se), indicating that the stratabound ore at Xinqiao formed from multiple pulses of magmatic-hydrothermal fluids derived from an Early Cretaceous stock.Co, Ni, and Se enrichment in porphyry- and proximal skarn-type pyrite suggests they formed at relatively high temperature, whereas the colloform pyrite shows trace element contents (Cu, Pb, Zn, Ag, and Bi) similar to those in distal skarn pyrite, suggesting that they may have formed in the same fluid environment. The trace element variations in pyrite from stratabound, skarn and porphyry ore probably resulted from decreasing fluid temperature and increasing pH away from the source. Our data, combined with previous studies, show that Co and Ni in pyrite increase toward porphyry and skarn ore, whereas As, Sb, Pb, Ag, and Bi are enriched in pyrite in distal stratabound ore, which extends for 1–2 km away from the intrusion. A plot of As/Se vs. Co discriminates the three ore types that occur associated with porphyry-skarn Cu systems in the Middle and Lower Yangtze belt (MLYB). These results indicate pyrite chemistry can be effective in discriminating the genesis of different deposit types related to porphyry-skarn systems and can potentially be used as a vectoring tool during exploration in the MLYB and elsewhere.

Crustal architecture of the south-east Superior Craton and controls on mineral systems

Crustal and lithospheric architecture provide a first-order control on Earth evolution, including mineral systems. The ability to understand the internal nature and margins of crustal and lithospheric blocks, in both space and time, is vital in order to use continent architecture as a predictive tool in mineral exploration. In this study, we use U-Pb-Hf-O-trace element (TE) geochemical data from zircon grains in felsic magmatic rocks to isotopically map the south-east Superior Craton, producing a time-constrained architecture of the Archean crust in this area. We then assess the localization of volcanogenic massive sulphide (VMS), komatiite-hosted Ni-Cu-PGE, and syn- to post-tectonic Au systems within that architecture, constraining the first-order crustal-scale controls on these mineral systems. In terms of zircon data, at ca. >2750–2695 Ma, the central and north-west Abitibi subprovince has more juvenile εHf, light to mantle-like δ18O, lower (Eu/Eu*)/Y*10000 (drier/shallower crust), reduced ΔFMQ, less continental initial-U (Ui)/Yb, and more mantle-like Ui/Nb, relative to surrounding crust. The syn-volcanic mineral systems are localised in this juvenile zone. At ca. 2704–2695 Ma, there is a marked transition in multiple datasets, including increases in δ18O, (Eu/Eu*)/Y*10000, ΔFMQ, Ui/Yb and Ui/Nb data, and a decrease in εHf. These data represent a more evolved continental signature and the transition to a relatively homogenous regional Hf-O-TE architecture. World-class orogenic gold mineralization occurring at ca. <2680 Ma is predominantly localized into the same region as the syn-volcanic deposits, demonstrating the profound role of early architecture on the localisation of later mineral systems.

Ranges of Physical Parameters and Geochemical Features of Mineralizing Fluids at Porphyry Deposits of Various Types of the Cu−Mo−Au System: Evidence from Fluid Inclusions Data

The paper reviews and summarizes data on the physicochemical parameters and chemical features of mineralizing fluids at porphyry deposits of the Cu–Mo–Au system. The calculated average values and ranges of parameters of the fluids in mineral-hosted fluid inclusions at porphyry deposits are as follows: temperature 90–957 °C, average 388 °C; salinity 0.1–88.0 wt % equiv. NaCl, average 29.4 wt % equiv. NaCl; and density 0.38–1.85 g/cm3, average 0.93 g/cm3. The highest average temperature and the highest maximum homogenization temperatures of the fluids were detected at deposits of the Cu (Au) type, with both values systematically decreasing with the transition to the Cu, Mo (Au), and then to Mo and Au types of porphyry deposits. The situations with the average and maximum salinity values of the fluids and their density are analogous. The data in the literature on the concentrations of some elements are still insufficient to reliably characterize variations in these concentrations at all of the discussed types of porphyry deposits. The highest Cu and Fe concentrations were found in the highest temperature fluids at deposits of the Cu (Au) type. The maximum Mo concentrations were detected in fluids at porphyry Mo deposits, and the highest Ag concentrations occurred at porphyry Au deposits. The chemical composition of the mineralizing fluids is, thus, strongly correlated with the types of the porphyry deposits. The hypothesis is discussed: the geochemical specifics of mineralizing fluids at various types of porphyry deposits of the Cu–Mo–Au system are related to the depths at which fluid separated from the magmatic melt. A scenario is proposed for the separation of mineralizing fluids from granite melt at various depths for fluids that form different types of porphyry deposits.

Cyclic and tensile deformations of Gold–Silver core shell systems using newly parameterized MEAM potential

Gold–Silver (Au–Ag) core-shell nanostructures have significant applicability in stretchable and biocompatible electronics where endurance under high tensile and cyclic loading is a requirement. This work, for the first time, quantitatively investigates the role of dislocations and defect interaction governing the mechanical behavior of Au–Ag and Ag–Au Core-shell nanostructures under tensile and cyclic loading using molecular dynamics (MD) simulation. For accurate representation of the underlying physics, a novel modified embedded atomic model (MEAM) interatomic potential for pristine Au, Ag and their alloys is parameterized through two different density functional theory (DFT) schemes. Using the new potential for MD simulations, the cyclic loading properties of pristine and core-shell nanowires (NWs) in a strain range of −15%–15% for 10 cycles are conducted. The tensile behavior of pristine and core-shell NWs is also explored for temperatures between 300 K and 600 K. A comparative analysis between Core-shell structures and their pristine counterparts are carried out. Our results suggest that Ag–Au Core-shell NW exhibit superior stress-strain reversibility under cyclic loading among the structures examined. Ag–Au exhibit the highest dislocation formation and near-complete annihilation of defects consistently. Au–Ag also present improved cyclic loading properties than its pristine counterparts. For tensile loading, all four structures exhibited deterioration in strength with increasing temperature. Thermal softening is observed to be more prominent in Au–Ag core-shell NWs compared to Ag–Au. Our work lays out a foundation for exploration of mechanical properties of Au–Ag systems using the MEAM potential which will help design components for stretchable electronics and creates a pathway for further exploration of similar binary alloy systems.

Telluride-bearing Au-Ag mineralization in the Singu-Tabeikkyin gold District, Mogok metamorphic Belt, Myanmar: New constraints on an intermediate-sulfidation epizonal orogenic ore system

The Singu-Tabeikkyin gold district is located in the Mogok Metamorphic Belt in Myanmar. Gold mineralization in this district occurs in a set of mainly N − S trending quartz veins, which are associated with minor replacement zones and skarns. This study investigates the field geology, ore mineralogy, mineral chemistry, and fluid inclusion characteristics of three gold prospects (CG-1, CG-2, and CG-3) containing Au-Ag along with telluride assemblages. Gold has formed as two generations, and only the second gold mineralization stage is associated with major telluride assemblages. The tellurides are associated with chalcopyrite, a late generation of sphalerite, and electrum. The telluride phases identified in the study are hessite (Ag2Te), petzite (Ag2AuTe3), altaite (PbTe), tellurobismuthite (Bi2Te3), and tetradymite (Bi2Te2S), and unnamed Au-Ag telluride phases. Liquid-rich two-phase fluid inclusions have homogenization temperatures in the range of 174–310 °C, and salinities of 1–12 wt% NaCl equiv. The chlorite geothermometry in this study yielded a variable temperature range from as low as 250 °C to 380 °C, in general agreement with the fluid inclusion temperature range. The thermometric data, in conjunction with the analysis of telluride-sulfide phase stability, constrain the conditions of ore formation to logƒTe2 and logƒS2 values of − 17 to − 9.5, and of − 13.4 to − 12.5. The geological and mineralogical data and the reconstructed conditions of ore formation as well as high-grade metamorphic host rocks of gneiss, marble and calc-silicates suggest that the telluride bearing gold-silver mineralization in the Singu-Tabeikkyin gold district forms part of an intermediate-sulfidation epizonal orogenic Au system.

Heteropolymetallic Architectures as Snapshots of Transmetallation Processes at Different Degrees of Transfer.

Novel heteropolymetallic architectures have been built by integrating Pd, Au and Ag systems. The dinuclear [(CNC)(PPh3)Pd‐G11M(PPh3)](ClO4) (G11M=Au (3), Ag (4); CNC=2,6‐diphenylpyridinate) and trinuclear [{(CNC)(PPh3)Pd}2 G11M](ClO4) (G11M=Au (6), Ag (5)) complexes have been accessed or isolated. Structural and DFT characterization unveil striking interactions of one of the aryl groups of the CNC ligand(s) with the G11M center, suggesting these complexes constitute models of transmetallation processes. Further analyses allow to qualitatively order the degree of transfer, proving that Au promotes the highest one and also that Pd systems favor higher degrees than Pt. Consistently, Energy Decomposition Analysis calculations show that the interaction energies follow the order Pd−Au > Pt−Au > Pd−Ag > Pt−Ag. All these results offer potentially useful ideas for the design of bimetallic catalytic systems.