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(NH4)2WS4 is Silicon tetrafluoride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of eight ammonium molecules and four sulfanide;tungsten molecules.
(CH3)4NI is Silicon tetrafluoride-derived structured and crystallizes in the tetragonal P4/nmm space group. The structure is zero-dimensional and consists of two hydriodic acid molecules and two tetramethylammonium molecules.
(C4PH11Cl)2Cl2 is Silicon tetrafluoride-derived structured and crystallizes in the orthorhombic Pbca space group. The structure is zero-dimensional and consists of eight hydrochloric acid molecules and eight schembl8954575 molecules.
Silicon carbide is a technologically relevant material that can exist in various structural polymorphs, each with its own electronic properties. Through the controlled growth of abrupt interfaces between the polymorphs, systems with emergent properties arise from differences in local bonding and stacking sequences. Determining the structure of these interfaces provides important insights into predicting and ultimately controlling their properties. Here, in this study, we use multislice electron ptychography (MEP) to qualitatively and quantitatively analyze interfaces between 3C and 4H silicon carbide in three dimensions. Two distinct interfaces are investigated: a coherent interface between $(1\bar{1}1)$ (3C) and $(0001)$ (4H) , and an incoherent interface between $(1\bar{1}2)$ (3C) and $(1\bar{1}00)$ (4H) . At the coherent interface, MEP enables direct quantification of a sharp boundary with an inclined step, whereas at the incoherent interface, local atomic displacements are determined along dislocation cores. By quantifying the spatial distribution and atomic-scale structure of these interfaces in three dimensions, this study provides insight into the complexity of silicon carbide heteropolytype interfaces, paving the way for theoretical modeling and the development of design rules to achieve desired properties.
(C4H12N)2SO4 is Silicon tetrafluoride-derived structured and crystallizes in the tetragonal P4_2/nmc space group. The structure is zero-dimensional and consists of two sulfuric acid molecules and four tetramethylammonium molecules.
(ReO4)2O2 is Silicon tetrafluoride-like structured and crystallizes in the tetragonal I4_1/a space group. The structure is zero-dimensional and consists of four rhenium;tetrahydrate molecules and four water molecules.
(NH4)2SO4 is Silicon tetrafluoride-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four ammonium molecules and four azanium;sulfuric acid molecules.
Silicon anodes for lithium-ion batteries (LIBs) have the potential for higher energy density compared to conventionally used graphite-based LIB anodes. However, silicon anodes exhibit poor cycle and calendar lifetimes due to mechanical instabilities and high chemical and electrochemical reactivity with the carbonate-based electrolytes that are typically used in LIBs. In this work, we synthesize a pitch carbon-coated silicon nanoparticle composite active material for LIB anodes that exhibits reduced chemical reactivity with carbonate-based electrolytes compared to an uncoated silicon anode. Silicon primary particle sizes less than 10 nm diameter minimize micro-scale mechanical degradation of the anode composite, while conformal coatings of pitch carbon minimize the parasitic reactions between the silicon and the electrolyte. When matched with a high voltage NMC622 (LiNi 0.6 Mn 0.2 Co 0.2 O 2 ) cathode, the pitch carbon-coated silicon anode retains approximately 75% of its initial capacity at the end of 1000 cycles. Increasing the areal loading of the pitch carbon-coated silicon anodes to realize energy density improvements over graphite anodes results in severe mechanical degradation on the electrode level, highlighting a remaining challenge to be addressed in future work.
(NH3)2S2O3 is Silicon tetrafluoride-derived structured and crystallizes in the monoclinic C2 space group. The structure is zero-dimensional and consists of two ammonia molecules, six ammonium molecules, and four thiosulfuric acid molecules.
General Atomics Electromagnetic Systems (GA-EMS) together with The Nonwovens Institute (NWI) and Harper International have executed on a development project to improve the production efficiency and reduce the production cost of silicon carbide (SiC) fiber – a critical material that advances US energy security and aerospace leadership. In the first budget period (BP1), the modified tow throughput (MTT) apparatus was developed, enabling fiber spinning in the form of loose coils rather than tightly packed spools (Figure 1) for batch processing of SiC fiber. This coil-based approach was proven to be capable of uniform fiber crosslinking and ceramic conversion, as well as demonstrating key process efficiencies while meeting the program fiber property targets.
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Abstract The performance of silicon carbide as an alternative plasma facing material (PFM) was studied at various irradiation conditions relevant to ion energies and fluxes of a fusion reactor. This analysis involves detailed modeling of subsurface plasma/material interactions, sputtered particle transport above the surface and redeposition, and related changes in material composition and microstructure induced by steady-state and Edge Localized Mode ion fluxes. Transition of a crystalline SiC surface to semi-crystalline and amorphous phases was analyzed based on advanced modeling of DIII-D tokamak experiments where SiC was irradiated in single- and multiple- L-mode and H-mode discharges. This analysis shows that displacement damage, particle deposition/redeposition, and D accumulation on the SiC divertor surface can lead to significant microstructural changes that result in enhanced sputtering erosion in comparison with the original crystalline material. However, the resulting total net erosion rate for a full-coverage, advanced tokamak, SiC coated divertor may well be acceptably low. Moreover, the C sputtering yield from the evolved SiC surface can be seven times lower than from a pure graphite surface; this would imply significantly reduced tritium co-deposition rates in a D-T tokamak reactor, compared with a pure carbon surface. It was also determined that chemical sputtering of both C and Si should not result in any noticeable effect on the net erosion, for attached plasma regimes. Our results thus show encouraging results overall for use of SiC as a PFM in tokamaks.
(C3H7NH3)2TeCl6 is Silicon tetrafluoride-derived structured and crystallizes in the cubic Pa-3 space group. The structure is zero-dimensional and consists of eight trimethylazanium molecules and four TeCl6 clusters. In each TeCl6 cluster, Te2- is bonded in an octahedral geometry to six equivalent Cl1- atoms. All Te–Cl bond lengths are 2.58 Å. Cl1- is bonded in a single-bond geometry to one Te2- atom.
(C3H7NH3)2SnCl6 is Silicon tetrafluoride-derived structured and crystallizes in the cubic Pa-3 space group. The structure is zero-dimensional and consists of eight trimethylazanium molecules and four SnCl6 clusters. In each SnCl6 cluster, Sn2+ is bonded in an octahedral geometry to six equivalent Cl1- atoms. All Sn–Cl bond lengths are 2.48 Å. Cl1- is bonded in a single-bond geometry to one Sn2+ atom.
(InSe2)2N2 is Silicon Disuphide-derived structured and crystallizes in the tetragonal I4/mcm space group. The structure is one-dimensional and consists of four ammonia molecules and two InSe2 ribbons oriented in the (0, 0, 1) direction. In each InSe2 ribbon, In3+ is bonded to four equivalent Se2- atoms to form distorted edge-sharing InSe4 tetrahedra. All In–Se bond lengths are 2.65 Å. Se2- is bonded in an L-shaped geometry to two equivalent In3+ atoms.
(NH4)4HgBr6 is Silicon tetrafluoride-derived structured and crystallizes in the tetragonal P4/mnc space group. The structure is zero-dimensional and consists of eight ammonium molecules and two HgBr6 clusters. In each HgBr6 cluster, Hg2+ is bonded in a distorted octahedral geometry to six Br1- atoms. There are two shorter (2.55 Å) and four longer (3.24 Å) Hg–Br bond lengths. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Hg2+ atom. In the second Br1- site, Br1- is bonded in a 1-coordinate geometry to one Hg2+ atom.
(NH4)2SiF6 is Silicon tetrafluoride-derived structured and crystallizes in the hexagonal P6_3mc space group. The structure is zero-dimensional and consists of four ammonium molecules and two SiF6 clusters. In each SiF6 cluster, Si4+ is bonded in an octahedral geometry to six F1- atoms. There is three shorter (1.72 Å) and three longer (1.73 Å) Si–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Si4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Si4+ atom.