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Results for “HYDROGEN FLUORIDE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Novel gas exposure system for the controlled exposure of plants to gaseous hydrogen fluoride

Abstract Plants can serve as sensitive bioindicators of the presence of contaminant vapors in the atmosphere. This work describes a novel laboratory-based gas exposure system capable of calibrating plants as bioindicators for the detection and delineation of the atmospheric contaminant hydrogen fluoride (HF) as a preparatory step for monitoring release emissions. To evaluate changes in plant phenotype and stress-induced physiological effects attributed to HF alone, the gas exposure chamber must have additional controls to simulate otherwise optimal plant growth conditions including variables such as light intensity, photoperiod, temperature, and irrigation. The exposure system was designed to maintain constant growth conditions during a series of independent experiments that varied between optimal (control) and stressful (HF exposure) conditions. The system was also designed to ensure the safe handling and application of HF. An initial system calibration introduced HF gas into the exposure chamber and monitored HF concentrations by cavity ring-down spectroscopy for a 48-h period. Stable concentrations inside the exposure chamber were observed after approximately 15 h, and losses of HF to the system ranged from 88 to 91%. A model plant species ( Festuca arundinacea ) was then exposed to HF for 48 h. Visual phenotype stress-induced responses aligned with symptoms reported in the literature for fluoride exposure (tip dieback and discoloration along the dieback transition margin). Fluoride concentrations in exposed tissues compared to control tissues confirmed enhanced fluoride uptake due to HF exposure. The system described herein can be applied to other reactive atmospheric pollutants of interest in support of bioindicator research.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

siRNA high throughput screening identifies regulators of chloropicrin and hydrogen fluoride injury in human corneal epithelial cell models

Corneal injuries induced by various toxicants result in similar clinical presentations such as corneal opacity and neovascularization. Many studies suggest that several weeks post-exposure a convergence of the molecular mechanisms drives these progressive pathologies. However, chemical agents vary in toxicological properties, and early molecular responses are anticipated to be somewhat dissimilar for different toxicants. In this report we chose 3120 targets from the Dharmacon Human Druggable genome to screen for chloropicrin (CP) and hydrogen fluoride (HF) corneal injury as we hypothesized that targets identified in vitro may be effective as therapeutic targets in future studies. Human immortalized corneal epithelial cells (SV40-HCEC) were used for screening. Cell viability and IL-8 were analyzed to down-select hits into validation studies, where multiplex cytokine analysis and high content analysis were performed to understand toxicant effect and target function. Some endpoints were also evaluated in a second human immortalized corneal epithelial cell line, TCEpi. Over 20 targets entered validation studies for CP and HF; of these, only three targets were shared: NR3C1, RELA, and KMT5A. These findings suggest that early molecular responses to different toxicants may be somewhat distinctive and present dissimilar targets for possible early intervention.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Low-temperature etching of silicon oxide and silicon nitride with hydrogen fluoride

Etching of high aspect ratio features into alternating SiO 2 and SiN layers is an enabling technology for the manufacturing of 3D NAND flash memories. In this paper, we study a low-temperature or cryo plasma etch process, which utilizes HF gas together with other gas additives. Compared with a low-temperature process that uses separate fluorine and hydrogen gases, the etching rate of the SiO 2 /SiN stack doubles. Both materials etch faster with this so-called second generation cryo etch process. Pure HF plasma enhances the SiN etching rate, while SiO 2 requires an additional fluorine source such as PF 3 to etch meaningfully. Further, the insertion of H 2 O plasma steps into the second generation cryo etch process boosts the SiN etching rate by a factor of 2.4, while SiO 2 etches only 1.3 times faster. We observe a rate enhancing effect of H 2 O coadsorption in thermal etching experiments of SiN with HF. Ammonium fluorosilicate (AFS) plays a salient role in etching of SiN with HF with and without plasma. AFS appears weakened in the presence of H 2 O. Density functional theory calculations confirm the reduction of the bonding energy when NH 4 F in AFS is replaced by H 2 O.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on H4NF2 by Materials Project

N2(H2)3(HF2)2 crystallizes in the trigonal R-3m space group. The structure is zero-dimensional and consists of six hydrogen fluoride hydrogen fluoride molecules, six molecular hydrogen molecules, and three nitrogen molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H5NF2 by Materials Project

NH4HF2 is High Pressure (4-7GPa) Tellurium structured and crystallizes in the orthorhombic Pmna space group. The structure is zero-dimensional and consists of four ammonium molecules and four hydrogen fluoride hydrogen fluoride molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H13C4NF2 by Materials Project

N(CH3)4HF2 is Silicon tetrafluoride-derived structured and crystallizes in the orthorhombic Pmmn space group. The structure is zero-dimensional and consists of two hydrogen fluoride hydrogen fluoride molecules and two tetramethylammonium molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KH(IF6)2 by Materials Project

K(IF5)2HF2 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional and consists of four hydrogen fluoride hydrogen fluoride molecules and one K(IF5)2 framework. In the K(IF5)2 framework, K1+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All K–F bond lengths are 2.69 Å. I5+ is bonded in a 5-coordinate geometry to five F1- atoms. There is one shorter (1.88 Å) and four longer (1.95 Å) I–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one I5+ atom. In the second F1- site, F1- is bonded in a distorted linear geometry to one K1+ and one I5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeH14C3S3(N3F2)2 by Materials Project

C3H13TeS3(N3F)2HF2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four hydrogen fluoride hydrogen fluoride molecules and two C3H13TeS3(N3F)2 clusters. In each C3H13TeS3(N3F)2 cluster, there are three inequivalent C+3.33+ sites. In the first C+3.33+ site, C+3.33+ is bonded in a distorted bent 120 degrees geometry to two N3- and one S2- atom. Both C–N bond lengths are 1.33 Å. The C–S bond length is 1.75 Å. In the second C+3.33+ site, C+3.33+ is bonded in a distorted trigonal planar geometry to two N3- and one S2- atom. Both C–N bond lengths are 1.33 Å. The C–S bond length is 1.74 Å. In the third C+3.33+ site, C+3.33+ is bonded in a distorted trigonal planar geometry to two N3- and one S2- atom. There is one shorter (1.30 Å) and one longer (1.34 Å) C–N bond length. The C–S bond length is 1.79 Å. There are six inequivalent N3- sites. In the first N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the third N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. Both N–H bond lengths are 1.03 Å. In the fourth N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. There is one shorter (1.01 Å) and one longer (1.02 Å) N–H bond length. In the fifth N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the sixth N3- site, N3- is bonded in a trigonal planar geometry to one C+3.33+ and two H1+ atoms. There is one shorter (1.02 Å) and one longer (1.25 Å) N–H bond length. There are thirteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one S2- and one F1- atom. The H–S bond length is 2.04 Å. The H–F bond length is 0.99 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the tenth H1+ site, H1+ is bonded in a linear geometry to one N3- and one F1- atom. The H–F bond length is 1.17 Å. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. Te4+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are a spread of Te–S bond distances ranging from 2.45–3.27 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to one C+3.33+, one H1+, and two equivalent Te4+ atoms. In the second S2- site, S2- is bonded in a water-like geometry to one C+3.33+ and one Te4+ atom. In the third S2- site, S2- is bonded in a distorted T-shaped geometry to one C+3.33+, one Te4+, and one F1- atom. The S–F bond length is 2.77 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one H1+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one H1+ and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H3F2 by Materials Project

H2(HF)4 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of one hydrogen molecule and two hydrogen fluoride hydrogen fluoride molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HXe2F15 by Materials Project

(XeF6)4(HF2)2F2 crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of four hydrofluoric acid molecules, four hydrogen fluoride hydrogen fluoride molecules, and four XeF6 clusters. In each XeF6 cluster, there are two inequivalent Xe sites. In the first Xe site, Xe is bonded in a 7-coordinate geometry to seven F atoms. There are a spread of Xe–F bond distances ranging from 1.98–2.51 Å. In the second Xe site, Xe is bonded in a 7-coordinate geometry to seven F atoms. There are a spread of Xe–F bond distances ranging from 1.98–2.48 Å. There are twelve inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Xe atom. In the second F site, F is bonded in a single-bond geometry to one Xe atom. In the third F site, F is bonded in a single-bond geometry to one Xe atom. In the fourth F site, F is bonded in a single-bond geometry to one Xe atom. In the fifth F site, F is bonded in a single-bond geometry to one Xe atom. In the sixth F site, F is bonded in a single-bond geometry to one Xe atom. In the seventh F site, F is bonded in a single-bond geometry to one Xe atom. In the eighth F site, F is bonded in a single-bond geometry to one Xe atom. In the ninth F site, F is bonded in a bent 120 degrees geometry to two Xe atoms. In the tenth F site, F is bonded in a single-bond geometry to one Xe atom. In the eleventh F site, F is bonded in a bent 120 degrees geometry to two Xe atoms. In the twelfth F site, F is bonded in a single-bond geometry to one Xe atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H25C8IN2(OF2)2 by Materials Project

(N(CH3)4)2HF2I(OF)2 is Silicon tetrafluoride-derived structured and crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of four hydrogen fluoride hydrogen fluoride molecules, eight tetramethylammonium molecules, and four I(OF)2 clusters. In each I(OF)2 cluster, O2- is bonded in a single-bond geometry to one I1- atom. The O–I bond length is 1.80 Å. I1- is bonded in a distorted rectangular see-saw-like geometry to two equivalent O2- and two F1- atoms. Both I–F bond lengths are 2.08 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one I1- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one I1- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te3(OF6)2 by Materials Project

Te3(OF4)2(F2)2 crystallizes in the tetragonal I4_1/a space group. The structure is zero-dimensional and consists of sixteen hydrogen fluoride hydrogen fluoride molecules and eight Te3(OF4)2 clusters. In each Te3(OF4)2 cluster, there are two inequivalent Te+5.33+ sites. In the first Te+5.33+ site, Te+5.33+ is bonded in a trigonal pyramidal geometry to one O2- and three F1- atoms. The Te–O bond length is 2.01 Å. There are a spread of Te–F bond distances ranging from 1.86–1.95 Å. In the second Te+5.33+ site, Te+5.33+ is bonded in a square co-planar geometry to two equivalent O2- and two equivalent F1- atoms. Both Te–O bond lengths are 2.00 Å. Both Te–F bond lengths are 1.98 Å. O2- is bonded in a distorted bent 150 degrees geometry to two Te+5.33+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Te+5.33+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Te+5.33+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one Te+5.33+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Te+5.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sb2HF13 by Materials Project

Sb2F11HF2 is Tungsten Carbide structured and crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one hydrogen fluoride hydrogen fluoride molecule and one Sb2F11 cluster. In the Sb2F11 cluster, Sb is bonded to six F atoms to form corner-sharing SbF6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Sb–F bond distances ranging from 1.89–2.08 Å. There are six inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Sb atom. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom. In the fifth F site, F is bonded in a single-bond geometry to one Sb atom. In the sixth F site, F is bonded in a linear geometry to two equivalent Sb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Elucidating the Redox Behavior during Atomic Layer Deposition on Lithium-Ion Battery Cathode Materials

Atomic layer deposition (ALD) has emerged as a promising technology for applying ultrathin protective coatings on lithium-ion battery (LIB) cathode surfaces to improve their cycling stability. While there have been numerous reports evaluating the electrochemical performance of these surface-modified cathode materials, the chemical changes induced on the surface of the cathode materials upon ALD coating are not fully studied. This paper describes a systematic investigation to understand the interfacial changes of 12 different cathode materials upon coating with aluminum oxide (Al 2 O 3 ) using trimethyl aluminum (TMA) and H 2 O, and aluminum fluoride (AlF 3 ) using TMA and hydrogen fluoride pyridine (HFPy). Here, the surface composition of these cathode materials, which range from simple transition metal oxides (e.g. NiO and MnO) to complex multi-element cathode materials (e.g. LiNi x Mn 1-x-y Co y O 2 , NMC), was studied via X-ray photoelectron spectroscopy (XPS). The XPS measurements reveal that the transition metals in the cathode materials undergo selective oxidation/reduction depending upon the nature of the precursor, the coating, and the cathode material. The ability to chemically modify the surface of cathode materials via vapor-phase precursor adsorption will open new avenues to systematically control the interface of the cathode materials in LIBs that are not possible by conventional coating methods.

25 ENERGY STORAGE↗
DOE OSTI2022

Many-fermion simulation from the contracted quantum eigensolver without fermionic encoding of the wave function

Quantum computers potentially have an exponential advantage over classical computers for the quantum simulation of many-fermion quantum systems. Nonetheless, fermions are more expensive to simulate than bosons due to the fermionic encoding—a mapping by which the qubits are encoded with fermion statistics. Here we generalize the contracted quantum eigensolver (CQE) to avoid fermionic encoding of the wave function. In contrast to the variational quantum eigensolver, the CQE solves for a many-fermion stationary state by minimizing the contraction (projection) of the Schrödinger equation onto two fermions. We avoid fermionic encoding of the wave function by contracting the Schrödinger equation onto an unencoded pair of particles. Solution of the resulting contracted equation by a series of unencoded two-body exponential transformations generates an unencoded wave function from which the energy and two-fermion reduced density matrix (2-RDM) can be computed. We apply the unencoded and the encoded CQE algorithms to the hydrogen fluoride molecule, the dissociation of oxygen O 2 , and a series of hydrogen chains. Both algorithms show comparable convergence towards the exact ground-state energies and 2-RDMs, but the unencoded algorithm has computational advantages in terms of state preparation and tomography.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2022

Decomposition of PVDF to delaminate cathode materials from end-of-life lithium-ion battery cathodes

The growing demand of electric vehicles and rapid consumption of rechargeable lithium-ion batteries (LIBs) require recycling of spent cathode active materials (CAMs) to reduce hazardous wastes and supply raw materials to LIB production. To separate CAMs from the cathode, direct calcination of polyvinylidene fluoride (PVDF) binder is widely applied, which leads to high energy consumption and release of toxic hydrogen fluoride. It is desirable to have an environmentally friendly and effective alternative to traditional direct calcination. In this study, five lithium salts, LiOAc (lithium acetate), LiNO 3 , LiCl, Li 2 CO 3 , and Li 2 SO 4 , were deployed and compared for their performance in recycling CAMs. A peel-off efficiency of up to 98.5% was achieved at a LiOAc to LiNO 3 molar ratio of 3:2, salt to cathode mass ratio of 10:1, and temperature of 300 °C at a holding time of 30 min. This system avoids corrosive chemicals and minimizes particle agglomeration of recycled products. Compared with sodium salt systems (NaOAc-NaNO 3 ) or direct calcination, the LiOAc-LiNO 3 system prevented high reaction temperature or further lithium loss and minimized crystal structure and morphological changes. In conclusion, a decomposition mechanism of PVDF through adsorption of HF and fluorine substitution was proposed.

25 ENERGY STORAGE↗
DOE OSTI2021

Comparison of AlF 3 thin films grown by thermal and plasma enhanced atomic layer deposition

Films of aluminum fluoride (AlF 3 ) deposited by thermal and plasma enhanced atomic layer deposition (PEALD) have been compared using in situ multiwavelength ellipsometry (MWE) and monochromatic x-ray photoelectron spectroscopy (XPS). The AlF 3 films were grown using cyclic exposures of trimethylaluminum, hydrogen fluoride, and H radicals from a remote H 2 inductively coupled plasma. Films were characterized in situ using MWE and XPS for growth rate, film composition, and impurity incorporation. The MWE showed a growth rate of 1.1 and 0.7 Å per cycle, at 100 °C, for thermal and plasma enhanced ALD AlF 3 films, respectively. Carbon incorporation was below the XPS detection limit. The plasma enhanced ALD AlF 3 film showed the presence of Al-Al chemical states, in the Al 2p scans, suggesting the presence of Al-rich clusters with a concentration of 14%. The Al-rich clusters are thought to originate during the hydrogen plasma step of the PEALD process. Finally, the Al-rich clusters were not detected in thermal ALD AlF 3 films using the same precursors and substrate temperature.

36 MATERIALS SCIENCE↗