Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

The composition of the fluid phase in inclusions in synthetic HPHT diamonds grown in system Fe-Ni-Ti-C.

ABSTRACT: Diamonds grown by high pressure high temperature process (HPHT) are usually characterized by yellow color and high contents of nitrogen. Introduction of Ti decreases nitrogen content in diamond. Understanding the formation of nitrogen-poor diamond is very important not for the progress of HPHT process only, but because these diamond varieties represent the rare natural stones, although their crystallization conditions have not been clarified yet. Here we studied the composition of fluid phase in synthetic diamonds. The experiments were performed using a high-pressure apparatus BARS at pressures 5.5-6.0 GPa and temperatures 1350-1400 °C. It was found that introduction of metallic Ti leads to concentration of nitrogen mainly as nitrogenated hydrocarbons. The hypothesis that elucidates the formation of low-nitrogen diamond in Fe-Ni is proposed: the presence of Ti leads to an increase of hydrogen fugacity in the metal melt which drastically reduces the nitrogen solubility. As a result, nitrogen concentrates in the form of complex hydrocarbon compounds, while diamond grows colorless and characterized by very low nitrogen content. It is suggested that the proposed mechanism acts the same way in the presence of other metals which are strong reducing agents.

SUBMITTER: Sonin V

PROVIDER: S-EPMC8786936 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Melting of sediments in the deep mantle produces saline fluid inclusions in diamonds.

Project description:Diamonds growing in the Earth's mantle often trap inclusions of fluids that are highly saline in composition. These fluids are thought to emerge from deep in subduction zones and may also be involved in the generation of some of the kimberlite magmas. However, the source of these fluids and the mechanism of their transport into the mantle lithosphere are unresolved. Here, we present experimental results showing that alkali chlorides are stable solid phases in the mantle lithosphere below 110 km. These alkali chlorides are formed by the reaction of subducted marine sediments with peridotite and show identical K/Na ratios to fluid inclusions in diamond. At temperatures >1100°C and low pressures, the chlorides are unstable; here, potassium is accommodated in mica and melt. The reaction of subducted sediments with peridotite explains the occurrence of Mg carbonates and the highly saline fluids found in diamonds and in chlorine-enriched kimberlite magmas.

| S-EPMC6541459 | biostudies-literature

Synthetic Designs and Structural Investigations of Biomimetic Ni-Fe Thiolates.

Project description:Described are the syntheses of several Ni(?-SR)2Fe complexes, including hydride derivatives, in a search for improved models for the active site of [NiFe]-hydrogenases. The nickel(II) precursors include (i) nickel with tripodal ligands: Ni(PS3)- and Ni(NS3)- (PS33- = tris(phenyl-2-thiolato)phosphine, NS33- = tris(benzyl-2-thiolato)amine), (ii) traditional diphosphine-dithiolates, including chiral diphosphine R,R-DIPAMP, (iii) cationic Ni(phosphine-imine/amine) complexes, and (iv) organonickel precursors Ni( o-tolyl)Cl(tmeda) and Ni(C6F5)2. The following new nickel precursor complexes were characterized: PPh4[Ni(NS3)] and the dimeric imino/amino-phosphine complexes [NiCl2(PCH?NAn)]2 and [NiCl2(PCH2NHAn)]2 (P = Ph2PC6H4-2-). The iron(II) reagents include [CpFe(CO)2(thf)]BF4, [Cp*Fe(CO)(MeCN)2]BF4, FeI2(CO)4, FeCl2(diphos)(CO)2, and Fe(pdt)(CO)2(diphos) (diphos = chelating diphosphines). Reactions of the nickel and iron complexes gave the following new Ni-Fe compounds: Cp*Fe(CO)Ni(NS3), [Cp(CO)Fe(?-pdt)Ni(dppbz)]BF4, [( R,R-DIPAMP)Ni(?-pdt)(H)Fe(CO)3]BArF4, [(PCH?NAn)Ni(?-pdt)(Cl)Fe(dppbz)(CO)]BF4, [(PCH2NHAn)Ni(?-pdt)(Cl)Fe(dppbz)(CO)]BF4, [(PCH?NAn)Ni(?-pdt)(H)Fe(dppbz)(CO)]BF4, [(dppv)(CO)Fe(?-pdt)]2Ni, {H[(dppv)(CO)Fe(?-pdt)]2Ni]}BF4, and (C6F5)2Ni(?-pdt)Fe(CO)2(dppv) (DIPAMP = (CH2P(C6H4-2-OMe)2)2; BArF4- = [B(C6H3-3,5-(CF3)2]4-)) Within the context of Ni-(SR)2-Fe complexes, these new complexes feature new microenvironments for the nickel center: tetrahedral Ni, chirality, imine, and amine coligands, and Ni-C bonds. In the case of {H[(dppv)(CO)Fe(?-pdt)]2Ni}+, four low-energy isomers are separated by ?3 kcal/mol, one of which features a biomimetic HNi(SR)4 site, as supported by density functional theory calculations.

| S-EPMC6379113 | biostudies-literature

Basicity and Electrolyte Composition Dependent Stability of Ni-Fe-S and Ni-Mo Electrodes during Water Splitting.

Project description:Non-noble metal electro-catalysts for water splitting are highly desired when we are moving towards a society where green electrons are becoming abundantly available, offering clear prospects to make our society more sustainable. In this work, Ni-Fe-S is reported as a high performing anode material for the water splitting reaction, operating at low overpotentials and showing high apparent stability. Furthermore, Ni-Mo electrodes are developed on metallic foam substrates and optimized in terms of their performance. The Ni-Fe-S material as anode, combined and integrated with Ni-Mo as cathode in a cell configuration, splits water at 10?mA?cm-2 and a potential of 1.55?V. Similar to previous reports, we confirm that Mo leaches from Ni-Mo/Ni foam electrodes. Cycling tests and ICP-AES measurements show that the stability of Ni-Fe-S is apparent, and that in reality S is leaching from the material as was already suggested in literature. We expand on this knowledge and show that the leaching of S is dependent on both pH and the cation used during electrocatalysis. Furthermore, we find that applying an oxidative potential is in truth stabilizing towards S and that the alkalinity causes leaching. S was furthermore mobile and found to segregate towards the surface. Finally, using too low pH values (11 and lower) result in the passivating hydroxide metal layers being destroyed and the Ni-Fe-S dissolving completely.

| S-EPMC7155041 | biostudies-literature

Bulk TiB₂-Based Ceramic Composites with Improved Mechanical Property Using Fe-Ni-Ti-Al as a Sintering Aid.

Project description:The densification behavior, microstructure and mechanical properties of bulk TiB₂-based ceramic composites, fabricated using the spark plasma sintering (SPS) technique with elements of (Fe-Ni-Ti-Al) sinter-aid were investigated. Comparing the change of shrinkage displacement of pure TiB₂ and TiB₂-5 wt% (Fe-Ni-Ti-Al), the addition of elements Fe-Ni-Ti-Al into TiB₂ can facilitate sintering of the TiB₂ ceramics. As the sintering temperature exceeds 1300 °C, the relative density does not significantly change. Alumina particles and austenite (Fe-Ni-Ti) metallic binder distributed homogeneously in the grain boundary of TiB₂ can inhibit the growth of the TiB₂ grains when the sintering temperature is below 1300 °C. The density and particle size of TiB₂ greatly influence the mechanical behavior of TiB₂-5 wt% (Fe-Ni-Ti-Al) composites. The specimen sintered at 1300 has the highest microhardness of 21.1 ± 0.1 GPa with an elastic modulus of 461.4 GPa. The content of secondary borides (M₂B, being M = Fe, Ni), which are more brittle than TiB₂ particles, can also influence the fracture toughness. The specimen sintered at 1500 °C has the highest fracture toughness of 6.16 ± 0.30 MPa·m1/2 with the smallest M₂B phase. The results obtained provide insight into fabrication of ceramic composites with improved mechanical property.

| S-EPMC5456019 | biostudies-other

Enhanced Fe-Centered Redox Flexibility in Fe-Ti Heterobimetallic Complexes.

Project description:Previously, we reported the synthesis of Ti[N( o-(NCH2P( iPr)2)C6H4)3] and the Fe-Ti complex, FeTi[N( o-(NCH2P( iPr)2)C6H4)3], abbreviated as TiL (1), and FeTiL (2), respectively. Herein, we describe the synthesis and characterization of the complete redox families of the monometallic Ti and Fe-Ti compounds. Cyclic voltammetry studies on FeTiL reveal both reduction and oxidation processes at -2.16 and -1.36 V (versus Fc/Fc+), respectively. Two isostructural redox members, [FeTiL]+ and [FeTiL]- (2ox and 2red, respectively) were synthesized and characterized, along with BrFeTiL (2-Br) and the monometallic [TiL]+ complex (1ox). The solid-state structures of the [FeTiL]+/0/- series feature short metal-metal bonds, ranging from 1.94-2.38 Å, which are all shorter than the sum of the Ti and Fe single-bond metallic radii (cf. 2.49 Å). To elucidate the bonding and electronic structures, the complexes were characterized with a host of spectroscopic methods, including NMR, EPR, and 57Fe Mössbauer, as well as Ti and Fe K-edge X-ray absorption spectroscopy (XAS). These studies, along with hybrid density functional theory (DFT) and time-dependent DFT calculations, suggest that the redox processes in the isostructural [FeTiL]+,0,- series are primarily Fe-based and that the polarized Fe-Ti π-bonds play a role in delocalizing some of the additional electron density from Fe to Ti (net 13%).

| S-EPMC6727590 | biostudies-literature

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles.

Project description:In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE.

| S-EPMC4651318 | biostudies-literature

Composite Photocatalysts with Fe, Co, and Ni Oxides on Supports with Tetracoordinated Ti Embedded into Aluminosilicate Gel during Zeolite Y Synthesis.

Project description:Ti-aluminosilicate gels were used as supports for the immobilization of Fe, Co, and Ni oxides (5%) by impregnation and synthesis of efficient photocatalysts for the degradation of β-lactam antibiotics from water. Titanium oxide (1 and 2%) was incorporated into the zeolite network by modifying the gel during the zeolitization process. The formation of the zeolite Y structure and its microporous structure were evidenced by X-ray diffraction and N2 physisorption. The structure, composition, reduction, and optical properties were studied by X-ray diffraction, H2-TPR, XPS, Raman, photoluminescence, and UV-Vis spectroscopy. The obtained results indicated a zeolite Y structure for all photocatalysts with tetracoordinated Ti4+ sites. The second transitional metals supported by the post-synthesis method were obtained in various forms, such as oxides and/or in the metallic state. A red shift of the absorption edge was observed in the UV-Vis spectra of photocatalysts upon the addition of Fe, Co, or Ni species. The photocatalytic performances were evaluated for the degradation of cefuroxime in water under visible light irradiation. The best results were obtained for iron-immobilized photocatalysts. Scavenger experiments explained the photocatalytic results and their mechanisms. A different contribution of the active species to the photocatalytic reactions was evidenced.

| S-EPMC10888282 | biostudies-literature

Highly active dry methane reforming catalysts with boosted in situ grown Ni-Fe nanoparticles on perovskite via atomic layer deposition.

Project description:With the need for more stable and active metal catalysts for dry reforming of methane, in situ grown nanoparticles using exsolution are a promising approach. However, in conventional exsolution, most nanoparticles remain underneath the surface because of the sluggish diffusion rate of cations. Here, we report the atomic layer deposition (ALD)-combined topotactic exsolution on La0.6Sr0.2Ti0.85Ni0.15O3-δ toward developing active and durable catalysts. The uniform and quantitatively controlled layer of Fe via ALD facilitates the topotactic exsolution, increasing finely dispersed nanoparticles. The introduction of Fe2O3 yields the formation of Ni-Fe alloy owing to the spontaneous alloy formation energy of -0.43 eV, leading to an enhancement of the catalytic activity for dry methane reforming with a prolonged stability of 410 hours. Overall, the abundant alloy nanocatalysts via ALD mark an important step forward in the evolution of exsolution and its application to the field of energy utilization.

| S-EPMC7449676 | biostudies-literature

A trinuclear Fe-Fe-Ni complex formed by ligand reshuffling.

Project description:The title complex, dicarbonyl-3?(2)C-(?(3)-3,6-dimethyl-3,6-diaza-octane-1,8-dithiol-ato-1:2:3?(7)S:S,N,N',S':S,S')(?(2)-3,6-di-methyl-3,6-diaza-octane-1,8-dithiol-ato-1:2?(5)S,N,N',S':S)-1,2-diiron(II)-3-nickel(0) [Fe(2)Ni(C(8)H(18)N(2)S(2))(2)(CO)(2)], is the second example showing M(?-SR)(2)Ni(0)(CO)(2) coordination (M = any metal atom). Both Fe(II) ions are five-coordinated in distorted trigonal-bipyramidal geometries by two N atoms and three S atoms. The Ni atom is four-coordinated in a distorted tetra-hedral geometry by two S atoms and two carbonyl ligands. One of the 3,6-dimethyl-3,6-diaza-octane-1,8-dithiol-ate ligands is disordered, the major component having a refined occupancy of 0.873?(2). The Fe?Fe distance is 3.0945?(3)Å and the Ni?Fe distance is 2.8505?(3)?Å.

| S-EPMC3120414 | biostudies-literature

(Fe,Ni)<sub>2</sub>P allabogdanite can be an ambient pressure phase in iron meteorites.

Project description:An orthorhombic modification of (Fe,Ni)2P, allabogdanite, found in iron meteorites was considered to be thermodynamically stable at pressures above 8 GPa and temperatures of 1673 K according to the results of recent static high-pressure and high-temperature experiments. A hexagonal polymorphic modification of (Fe,Ni)2P, barringerite, was considered to be stable at ambient conditions. Experimental investigation through the solid-state synthesis supported by ab initio calculations was carried out to clarify the stability fields of (Fe,Ni)2P polymorphs. Both experimental and theoretical studies show that Fe2P-allabogdanite is a low-temperature phase stable at ambient conditions up to a temperature of at least 773 K and, therefore, is not necessarily associated with high pressures. This is consistent with the textural relationships of allabogdanite in iron meteorites.

| S-EPMC7265559 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data