Materials Data on C(SN)2 by Materials Project
C(NS)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four 3h-1,2,3,5-dithiadiazole molecules and four 62251-12-1 molecules.
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C(NS)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four 3h-1,2,3,5-dithiadiazole molecules and four 62251-12-1 molecules.
Abstract The chemical interaction of Sn with H 2 by X‐ray diffraction methods at pressures of 180–210 GPa is studied. A previously unknown tetrahydride SnH 4 with a cubic structure ( fcc ) exhibiting superconducting properties below T C = 72 K is obtained; the formation of a high molecular C 2/ m ‐SnH 14 superhydride and several lower hydrides, fcc SnH 2 , and C 2‐Sn 12 H 18 , is also detected. The temperature dependence of critical current density J C (T) in SnH 4 yields the superconducting gap 2Δ(0) = 21.6 meV at 180 GPa. SnH 4 has unusual behavior in strong magnetic fields: B,T ‐linear dependences of magnetoresistance and the upper critical magnetic field B C2 (T) ∝ ( T C – T ). The latter contradicts the Wertheimer–Helfand–Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of fcc SnH 4 in non‐superconducting state exhibits a deviation from what is expected for phonon‐mediated scattering described by the Bloch‐Grüneisen model and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.
Weyl semimetal thin films with excellent crystalline quality are of great interest for antiferromagnetic spintronics. Mn 3 Sn is one Weyl semimetal with great properties and promise for exciting science and applications. It has proven very challenging, however, to grow Mn 3 Sn thin films with smooth surfaces, negligible strain, and excellent crystallinity. In this work, we discuss the successful preparation of epitaxial Mn 3 Sn (0001)-oriented thin films via molecular beam epitaxial growth on c -plane wurtzite GaN which was grown by MBE on Al 2 O 3 (0001). We present the reflection high energy electron diffraction analysis along with x-ray diffraction in order to demonstrate the crystalline quality of the film, and we give atomic models to explain the epitaxial orientation relationships between the crystal lattices of the substrate, GaN layer, and Mn 3 Sn layer. Importantly, we discuss the film lattice parameters as compared to expected values, demonstrating negligible strain both in-plane and out-of-plane . Atomic force microscopy reveals an epitaxial columnar growth mode characterized by flat-top-mesa islands, while scanning tunneling microscopy shows the atomically smooth surfaces of the mesa-top structures. Finally, Rutherford backscattering informs the stoichiometry of the film as well as the layer thicknesses.
The efficiencies of all-perovskite tandem devices are improving quickly. However, their complex interconnection layer (ICL) structures – with typically four or more layers deposited by different processes – limit their prospects for applications. Here, we report an ICL in all-perovskite tandem cells consisting merely of a fullerene layer and a SnO 2-x (0 60 layer is unintentionally n-doped by iodine ions from the perovskite and thus acts as an effective electron collecting layer. The SnO 2-x layer, formed by the incomplete oxidization of tin (x=1.76), has ambipolar carrier transport property enabled by the presence of a large density of Sn 2+ . The C 60 /SnO 1.76 ICL forms Ohmic contacts with both wide and narrow bandgap perovskite subcells with low contact resistivity. The ICL boosts the efficiencies of small-area tandem cells (5.9 mm 2 ) and large-area tandem cells (1.15 cm 2 ) to 24.4% and 22.2%, respectively. Lastly, the tandem cells remain 94% of its initial efficiency after continues 1-sun illumination for 1,000 hours.
(C)2SnCl2 crystallizes in the orthorhombic Imma space group. The structure is one-dimensional and consists of four 7772-99-8 molecules and two C ribbons oriented in the (1, 0, 0) direction. In each C ribbon, C is bonded in a linear geometry to two equivalent C atoms. Both C–C bond lengths are 1.32 Å.
Co 3 Sn 2 S 2 is a magnetic Weyl semimetal, in which ferromagnetic ordering at 177 K is predicted to stabilize Weyl points. We perform temperature and spatial dependent angle--resolved photoemission spectroscopy measurements through the Curie temperature (T c ), which show large band shifts and renormalization concomitant with the onset of magnetism. We argue that Co 3 Sn 2 S 2 evolves from a Mott ferromagnet below T c to a correlated metallic state above T c . To understand the magnetism, we derive a tight-binding model of Co-3d x 2 -y 2 orbitals on the kagome lattice. At the filling obtained by first-principles calculations, this model reproduces the ferromagnetic ground state, and results in the reduction of Coulomb interactions due to cluster effects. Using a disordered local moment simulation, we show how this reduced Hubbard U leads to a collapse of the bands across the magnetic transition, resulting in a correlated state which carries associated characteristic photoemission signatures that are distinct from those of a simple lifting of exchange splitting. Finally, the behavior of topology across T c is discussed in the context of this description of the magnetism.
Compound-specific isotope analysis (CSIA), position-specific isotope analysis (PSIA), and computational modeling (e.g., quantum mechanical models; reactive-transport models) are increasingly being used to monitor and predict biotic and abiotic transformations of organic contaminants in the field. However, identifying the isotope effect(s) associated with a specific transformation remains challenging in many cases. We describe and interpret the position-specific isotope effects of C and N associated with a SN 2 Ar reaction mechanism by a combination of CSIA and PSIA using quantitative 13 C nuclear magnetic resonance spectrometry, and density-functional theory, using 2,4-dinitroanisole (DNAN) as a model compound. The position-specific 13 C enrichment factor of O–C 1 bond at the methoxy group attachment site (ε C1 ) was found to be approximately -41‰, a diagnostic value for transformation of DNAN to its reaction products 2,4-dinitrophenol and methanol. Theoretical kinetic isotope effects calculated for DNAN isotopologues agreed well with the position-specific isotope effects measured by CSIA and PSIA. This combination of measurements and theoretical predictions demonstrates a useful tool for evaluating degradation efficiencies and/or mechanisms of organic contaminants and may promote new and improved applications of isotope analysis in laboratory and field investigations.
The expansion of sugarcane onto land currently occupied by improved (IMP) and semi-native (SN) pastures will reshape the U.S. bioenergy landscape. We combined biometric, ground-based and eddy covariance methods to investigate the impact of sugarcane expansion across subtropical Florida on the carbon (C) budget over a 3-year rotation. With 2.3- and 5.1-fold increase in productivity over IMP and SN pastures, sugarcane displayed a C use efficiency (CUE; i.e., fraction of gross C uptake allocated to plant growth) of 0.59, well above that of pastures (0.31–0.23). Sugarcane also had greater C allocation to aboveground productivity and hence, harvestable biomass relative to IMP and SN. Cane heterotrophic respiration over the 3-year rotation (903 ± 335 gC m −2 year −1 ) was 1% and 14% higher than IMP and SN pastures, respectively. These soil C losses responded largely to disturbance over the first year after conversion (1510 ± 227 gC m −2 year −1 ) but declined in subsequent years to an average 599 ± 90 gC m −2 year −1 —well below those of IMP (933 ± 140 gC m −2 year −1 ) and SN (759 ± 114 gC m −2 year −1 ) pastures—despite a significant 40%–61% increase in soil C inputs. Soil C inputs, however, shifted from root-dominated in pastures to litter-dominated in sugarcane, with only 5% C allocation to roots. Reduced decomposition rates in sugarcane were likely driven by changes in the recalcitrance and distribution rather than the size of the newly incorporated soil C pool. As a result, we observed a rapid shift in the net ecosystem C balance (NECB) of sugarcane from a large source immediately following conversion to approaching the net C losses of IMP pastures only 2 years after conversion. The environmental cost of converting pasture to sugarcane underscores the importance of implementing management practices to harness the soil C storage potential of sugarcane in advancing a sustainable bioeconomy in Southeastern United States.
CoSn and FeSn, two kagome-lattice metals, have recently attracted significant attention as hosts of electronic flat bands and emergent physical properties. However, current understandings of their physical properties are limited to knowledge of the average crystal structure. Here, we report the Fe-doping induced coemergence of the antiferromagentic (AFM) order and local symmetry breaking in (Co 0.45 Fe 0.55 )Sn. Rietveld analysis on the neutron and synchrotron X-ray diffraction data indicates A-type antiferromagnetic order with the moment pointing perpendicular to the kagome layers, associated with the anomaly in the MSn(1) 2 Sn(2) 4 (M = Co/Fe) octahedral distortion and the lattice constant c. Reverse Monte Carlo (RMC) modeling of the synchrotron X-ray total scattering results captured the subtle local orthorhombic distortion involving off-axis displacements of Sn(2). Our results indicate that the stable hexagonal lattice above T N becomes unstable once the A-type AFM order is formed below T N . Here we argue that the local symmetry breaking has a magnetic origin, since the spatially varied M–Sn(2) bond lengths arise from out-of-plane magnetic exchange coupling J c via the exchange pathway M–Sn(2)–M. Our study provides comprehensive information on the crystal structure in both long-range scale and local scale, unveiling unique coupling between AFM order, octahedral distortion, and hidden local symmetry breaking.
In this work, the chronic toxicity of an innovative Hg water treatment system using tin (Sn) (II) chloride (SnCl 2 ) followed by air stripping was assessed through measurements of survival, growth, and reproduction rate in the freshwater cladoceran Ceriodaphnia dubia, a model species for toxicity testing. We first calculated the concentrations of Hg causing 25% reduction in survival and reproduction (Lethal or Inhibition Concentrations, or LC 25 and IC 25 , for survival and reproduction, respectively) through exposure to aqueous Hg at concentrations ranging from 0 to 25,000 ng L -1 . Then, we treated media (DMW and natural stream water) contaminated with Hg at LC 25 and IC 25 concentrations with SnCl 2 at a Sn:Hg stoichiometric ratio of 8:1 and air stripping and exposed C. dubia to this Sn-amended media. Our results showed that Hg significantly affected survival, reproduction rates and impaired growth. SnCl 2 -treatment removed 100% of the Hg from the media at all concentrations tested with no deleterious effects on survival, growth and reproduction. Our results confirmed the efficacy of SnCl 2 in removing aqueous Hg from stream water and showed that the added Sn did not impact C. dubia at the concentrations tested, supporting the suitability of SnCl 2 -based treatments in appropriate Hg-contaminated environments.
A possible approach to reducing Nb 3 Sn magnet training is to increase the energy margin of Nb 3 Sn conductors by enhancing their specific heat (C p ). For this study, we have been developing Nb 3 Sn conductors with increased C p by incorporating substances with high C p at 2-10 K based on a conductor design that is compatible with standard Nb 3 Sn strand production. In the past couple of years our efforts have been mainly focused on improving strand design (e.g., position of high- C p filaments, thickness of the Cu tube for the high-C p filaments, ratio of the Cu powder to the high-C p substance, filament spacing, etc.) in order to obtain good strand drawability and to reduce degradation after rolling, which is needed for production of Rutherford cables. We also tried a new high-C p substance, Gd 2 O 2 S, and verified that it has much higher C p over the whole magnetic field range than the Gd 2 O 3 we used before. With that development work we can now produce high-C p strands with good drawability and low levels of degradation after rolling. This paper reports our findings and the current status of the development of high-C p Nb 3 Sn conductors.
Here we report ultra-high responsivity of epitaxial (Sn x Ga 1–x ) 2 O 3 (TGO) Schottky UV-C photodetectors and experimentally identified the source of gain as deep-level defects, supported by first principles calculations. Epitaxial TGO films were grown by plasma-assisted molecular beam epitaxy on (–201) oriented n-type β-Ga 2 O 3 substrates. Fabricated vertical Schottky devices exhibited peak responsivities as high as 3.5 ×10 4 A/W at –5 V applied bias under 250 nm illumination with sharp cutoff shorter than 280 nm and fast rise/fall time in milliseconds order. Hyperspectral imaging cathodoluminescence (CL) spectra were examined to find the mid-bandgap defects, the source of this high gain. Irrespective of different tin mole fractions, the TGO epilayer exhibited extra CL peaks at the green band (~2.20 eV) not seen in β-Ga 2 O 3 along with enhancement of the blue emission-band (~2.64 eV) and suppression of the UV emission-band. Based on hybrid functional calculations of the optical emission expected for defects involving Sn in β-Ga 2 O 3 , V Ga –Sn complexes are proposed as potential defect origins of the observed green and blue emission-bands. Such complexes behave as acceptors that can efficiently trap photogenerated holes and are predicted to be predominantly responsible for the ultra-high photoconductive gain in the Sn-alloyed Ga 2 O 3 devices by means of thermionic emission and electron tunneling. Regenerating the V Ga –Sn defect complexes by optimizing the growth techniques, we have demonstrated a planar Schottky UV-C photodetector of the highest peak responsivity.
Magnetism plays a key role in the emergence of topological phenomena in the Weyl semimetal Co 3 Sn 2 S 2 , which exhibits ferromagnetic interactions along the c-axis of the crystal and antiferromagnetic (AFM) interactions within the ab plane. Extensive studies on the temperature dependence of the magnetism with the magnetic field along the c-axis have uncovered a number of magnetic phases. Currently, the nature and origins of the reported magnetic phases are under debate. Here, in this work, we report on magnetic field orientation effects on the magnetism in Co 3 Sn 2 S 2 . The shape of the hysteresis loop of the Hall resistance at a fixed temperature is found to change from rectangular to bow tie-like as the magnetic field is tilted from the c-axis toward the ab plane, resembling that reported for magnetic fields along the c-axis as the temperature approaches the Curie temperature from below. Unlike their temperature-dependent counterparts, the newly observed bow tie-like hysteresis loops show exchange bias. Our results showcase the contribution of the in-plane AFM interactions to the magnetism in Co 3 Sn 2 S 2 and demonstrate a new way to tune its magnetic phases. They also shed light on the temperature-dependent magnetic phases occurring in the magnetic field along the c-axis of the crystal.
(C)4Sn(CS)2(C3N)2Sn3C20(N3S11)2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of four 1-azatricyclo[1.1.0.0^{2,4}]butane molecules; eight methane molecules; two Sn(CS)2 clusters; and one Sn3C20(N3S11)2 sheet oriented in the (0, 0, 1) direction. In each Sn(CS)2 cluster, Sn2+ is bonded in a linear geometry to two equivalent S2- atoms. Both Sn–S bond lengths are 3.05 Å. C2+ is bonded in a single-bond geometry to one S2- atom. The C–S bond length is 1.62 Å. S2- is bonded in a distorted bent 120 degrees geometry to one Sn2+ and one C2+ atom. In the Sn3C20(N3S11)2 sheet, there are two inequivalent Sn2+ sites. In the first Sn2+ site, Sn2+ is bonded in a distorted octahedral geometry to six S2- atoms. There are two shorter (2.33 Å) and four longer (2.66 Å) Sn–S bond lengths. In the second Sn2+ site, Sn2+ is bonded in an octahedral geometry to six S2- atoms. There are a spread of Sn–S bond distances ranging from 2.72–3.01 Å. There are six inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted bent 120 degrees geometry to two S2- atoms. There is one shorter (1.81 Å) and one longer (1.82 Å) C–S bond length. In the second C2+ site, C2+ is bonded in a distorted trigonal non-coplanar geometry to one N3- and two S2- atoms. The C–N bond length is 1.54 Å. There is one shorter (1.79 Å) and one longer (1.88 Å) C–S bond length. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.58 Å. In the fourth C2+ site, C2+ is bonded in a water-like geometry to two equivalent S2- atoms. Both C–S bond lengths are 1.69 Å. In the fifth C2+ site, C2+ is bonded in a distorted bent 120 degrees geometry to one N3- and one S2- atom. The C–N bond length is 1.42 Å. The C–S bond length is 1.64 Å. In the sixth C2+ site, C2+ is bonded in a distorted bent 120 degrees geometry to one N3- and one S2- atom. The C–N bond length is 1.35 Å. The C–S bond length is 1.74 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in an L-shaped geometry to two C2+ atoms. In the second N3- site, N3- is bonded in a 3-coordinate geometry to three C2+ atoms. There are six inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to two C2+ atoms. In the second S2- site, S2- is bonded in a 2-coordinate geometry to one Sn2+ and one C2+ atom. In the third S2- site, S2- is bonded in a water-like geometry to one Sn2+ and one C2+ atom. In the fourth S2- site, S2- is bonded in a single-bond geometry to one Sn2+ atom. In the fifth S2- site, S2- is bonded in a 2-coordinate geometry to one Sn2+ and two C2+ atoms. In the sixth S2- site, S2- is bonded in a distorted bent 120 degrees geometry to one Sn2+ and one C2+ atom.
The synthesis, crystal structure, and physical properties (magnetization, resistivity, heat capacity) in combination with theoretical calculations of the electronic structure and phonon properties are reported for intermetallic compounds LiPd 2 X ( X = Si, Ge, and Sn). LeBail refinement of powder x-ray diffraction data confirms that all compounds belong to the Heusler family (space group $\textit{F m-3m}$, No. 225). The lattice parameter increases with atomic size of X , and its value varies from $\textit{a}$ = 5.9059(4) Å for LiPd 2 Si and $\textit{a}$ = 6.0082(3)Å for LiPd 2 Ge, to $\textit{a}$ = 6.2644(1) Å for LiPd 2 Sn. The first compound, LiPd 2 Si, has apparently not been previously reported. All measured quantities demonstrate that LiPd 2 Ge exhibits superconductivity below $T_c$ = 1.96 K and the normal- and superconducting-state data indicate that it is a weak-strength type-I superconductor ($C/γT_c$ = 1.38) with electron-phonon coupling constant $λ_{e–p}$ = (0.53–0.56). LiPd 2 Si and LiPd 2 Sn are not superconducting above 1.68 K. The experimental observations are supported by theoretical calculations which show that LiPd 2 Ge has the highest computed $λ_{e–p}$ and $T_c$ of the group. A strong softening of the acoustic phonon mode is calculated, and in the case of X = Ge and Sn, imaginary phonon frequencies were computed. In this work, the soft mode is most pronounced in the case of LiPd 2 Ge, which suggests its correlation with superconductivity.
Sn(CCl)2 crystallizes in the orthorhombic Imma space group. The structure is one-dimensional and consists of two Sn(CCl)2 ribbons oriented in the (0, 1, 0) direction. Sn2+ is bonded in a tetrahedral geometry to two equivalent C and two equivalent Cl1- atoms. Both Sn–C bond lengths are 2.08 Å. Both Sn–Cl bond lengths are 2.34 Å. C is bonded in a linear geometry to one Sn2+ and one C atom. The C–C bond length is 1.23 Å. Cl1- is bonded in a single-bond geometry to one Sn2+ atom.
The rate and mechanism of the elimination of N 2 O from trans-R 3 Sn-O-N=N-O-SnR 3 (R = Ph ( 1 Ph ) and R = Cy ( 1 Cy )) to form R 3 Sn-O-SnR 3 (R = Ph ( 2 Ph ) and R = Cy ( 2 Cy )) have been studied using both NMR and IR techniques to monitor the reactions in the temperature range of 39–79 °C in C 6 D 6 . Activation parameters for this reaction are ΔH ‡ = 15.8 ± 2.0 kcal·mol –1 and ΔS ‡ = –28.5 ± 5 cal·mol –1 ·K –1 for 1 Ph and ΔH ‡ = 22.7 ± 2.5 kcal·mol –1 and ΔS ‡ = –12.4 ± 6 cal·mol –1 ·K –1 for 1 Cy . Addition of O 2 , CO 2 , N 2 O, or PPh 3 to sealed tube NMR experiments did not alter in a detectable way the rate or product distribution of the reactions. Computational DFT studies of elimination of hyponitrite from trans-Me 3 Sn-O-N=N-O-SnMe 3 ( 1 Me ) yield a mechanism involving initial migration of the R 3 Sn group from O to N passing through a marginally stable intermediate product and subsequent N 2 O elimination. Reactions of 1 Ph with protic acids HX are rapid and lead to formation of R 3 SnX and trans-H 2 N 2 O 2 . Reaction of 1 Ph with the metal radical •Cr(CO) 3 C 5 Me 5 at low concentrations results in rapid evolution of N 2 O. At higher •Cr(CO) 3 C 5 Me 5 concentrations, evolution of CO 2 rather than N 2 O is observed. Addition of 1 atm or less CO 2 to benzene or toluene solutions of 2 Ph and 2 Cy resulted in very rapid reaction to form the corresponding carbonates R 3 Sn-O-C(=O)-O-SnR 3 (R = Ph ( 3 Ph ) and R = Cy ( 3 Cy )) at room temperature. Evacuation results in fast loss of bound CO 2 and regeneration of 2 Ph and 2 Cy . Variable temperature data for formation of 3 Cy yield ΔH o = –8.7 ± 0.6 kcal·mol –1 , ΔS o = –17.1 ± 2.0 cal·mol –1 ·K –1 , and ΔG o 298K = –3.6 ± 1.2 kcal·mol –1 . Furthermore, DFT studies were performed and provide additional insight into the energetics and mechanisms for the reactions.
Co 3 Sn 2 S 2 has been reported to be a Weyl semimetal with c-axis ferromagnetism below a Curie temperature of 177 K. Despite the large interest in Co 3 Sn 2 S 2 , the magnetic structure is still unclear. Recent studies have challenged the magnetic phase diagram of Co 3 Sn 2 S 2 by reporting unusual magnetic phases including the presence of exchange bias. Here we show, using X-ray Magnetic Circular Dichroism, a shift in the magnetization hysteresis loop, reminiscent of exchange bias and establish that the magnetic moment in Co arises from the spin, with negligible orbital moment. At 6 K, using spatially-resolved angle-resolved photoemission spectroscopy, we detect a butterfly-shaped electronic band structure at small regions of the sample distinct from the known ferromagnetic band structure. Our density functional theory calculations suggest that the butterfly bands correspond to an antiferromagnetic phase. Separately, we detect a sharp flat band at the Fermi level at some regions in the sample, which we attribute to a surface state. These different electronic states found in a stoichiometric intermetallic invite further efforts to explore the origin and nature of the electronic inhomogeneity associated to magnetism on the mesoscale.