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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CoMoH24N6ClO7 by Materials Project

(H2MoO5)2(Co(NH3)6)2(H2O)4Cl2 crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four azane;cobalt molecules, four hydrochloric acid molecules, eight water molecules, and four H2MoO5 clusters. In each H2MoO5 cluster, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. All Mo–O bond lengths are 1.80 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.01 Å) and one longer (1.60 Å) H–O bond length. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Mo6+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Mo6+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Mo6+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to two H1+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2010

Conditions of Core Formation in the Early Earth: Single Stage or Heterogeneous Accretion?

Since approx.1990 high pressure and temperature (PT) experiments on metal-silicate systems have showed that partition coefficients [D(met/sil)] for siderophile (iron-loving) elements are much different than those measured at low PT conditions [1,2]. The high PT data have been used to argue for a magma ocean during growth of the early Earth [3,4]. In the ensuing decades there have been hundreds of new experiments carried out and published on a wide range of siderophile elements (> 80 experiments published for Ni, Co, Mo, W, P, Mn, V, Cr, Ga, Cu and Pd). At the same time several different models have been advanced to explain the siderophile elements in Earth's mantle: a) shallow depth magma ocean 25-30 GPa [3,5]; b) deep magma ocean; up to 50 GPa [6,7], and c) early reduced and later oxidized magma ocean [8,9]. Some studies have drawn conclusions based on a small subset of siderophile elements, or a set of elements that provides little leverage on the big picture (like slightly siderophile elements), and no single study has attempted to quantitatively explain more than 5 elements at a time. The purpose of this abstract is to identify issues that have lead to a difference in interpretation, and to present updated predictive expressions based on new experimental data. The resulting expressions will be applied to the siderophile element depletions in Earth's upper mantle.

Righter, Kevin↗
DOE OSTI2020

Electrolyte compositions comprising ionic liquids and metal hydride batteries comprising same

Electrolyte compositions comprising a) an ionic liquid and b) a protic acid and/or an organic solvent are suitable for use in electrochemical cells, e.g. metal hydride batteries. The electrolyte compositions may replace the currently employed 30% by weight aqueous KOH. Suitable protic acids include carboxylic acids, mineral acids, sulfonic acids and the like. Suitable organic solvents include organic carbonates, ethers, glymes, ortho esters, polyalkylene glycols, esters, lactones, glycols, formates, sulfones, sulfoxides, amides, alcohols, ketones, nitro solvents, nitrile solvents and combinations thereof. Present batteries may achieve a nominal open-circuit voltage of >1.2 V (volts) and up to about 6 V. The electrolyte compositions allow enlargement of the electrochemical window, thus allowing the use of further cathode active materials. Further cathode active materials include transition metals and their oxides, hydroxides and fluorides; for example, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt and Au and their oxides, hydroxides, oxide/hydroxides and fluorides.

25 ENERGY STORAGE↗
DOE OSTI2024

Metal DiSulfide thin films synthesized by pulsed ion beam ablation: Self-assembled structures with improved mechanical properties in humid conditions

Thin films composed of transition metal dichalcogenides such as molybdenum disulfide (MoS 2 ) or tungsten disulfide (WS 2 ) are well known for their solid lubricating behavior in dry environments such as space, but deteriorate rapidly in environments where oxygen is present. There have been many attempts over recent decades to improve MoS 2 lubricating performance in humid environments by addition of metals such as titanium to the film. The additions have come in the form of co-sputtering with the MoS 2 , or formation of nano multilayer coatings. We have previously reported on the synthesis of MoS 2 films by high-power ion beam ablation [Prasad et al, Matls. Lett. 65 (2010) 4–6]. The resulting films are observed to contain spheres of pure Mo of 10–100 nm size evenly dispersed throughout the ~1 μm-thick film, a form of self-assembly not before seen in films produced by sputtering or by pulsed laser deposition (PLD). The remaining Mosingle bondS matrix was observed to crystalize in situ under frictional contact into MoS 2 with the basal planes orienting themselves in the direction of sliding underneath the wear surface. The present study concerns metal additions in the form of alternating layers with MoS 2 deposited in between from an ablation target. The addition of Ti resulted in the extension of good tribological performance to humid air conditions, but the path to good performance appears to be relatively narrow. The same distributed Mo spheres were present in the new film, and similar self-assembled morphologies when V was substituted for the Ti, and when multilayers were formed of WS 2 with Zr additions. Furthermore, it appears that addition of Ti resulted in improvements in mechanical film strength that contributed to the wear ability in humid conditions.

Intense ion beams↗
DOE OSTI2020

Materials Data on Na3Co(Mo3O16)2 by Materials Project

Na3Co(Mo3O16)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.27–2.85 Å. In the second Na site, Na is bonded in a distorted octahedral geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.42–2.70 Å. There are three inequivalent Mo sites. In the first Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.58 Å. In the second Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.72–2.49 Å. In the third Mo site, Mo is bonded in a 4-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.37 Å. Co is bonded in an octahedral geometry to six O atoms. There are a spread of Co–O bond distances ranging from 1.77–1.91 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two Mo and one Co atom. In the second O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mo and one Co atom. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mo and one Co atom. In the fourth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the fifth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the seventh O site, O is bonded in a distorted T-shaped geometry to two equivalent Na and one Mo atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and one Mo atom. In the ninth O site, O is bonded in a single-bond geometry to one Mo atom. In the tenth O site, O is bonded in a single-bond geometry to one Mo atom. In the eleventh O site, O is bonded in a linear geometry to one Na and one Mo atom. In the twelfth O site, O is bonded in a distorted single-bond geometry to one Na and one Mo atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the fourteenth O site, O is bonded in a 3-coordinate geometry to two equivalent Na and one O atom. The O–O bond length is 1.25 Å. In the fifteenth O site, O is bonded in a single-bond geometry to one O atom. In the sixteenth O site, O is bonded in a single-bond geometry to one Na atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Preparation of 2D Polyaniline/MoO 3– x Superlattice Nanosheets via Intercalation-Induced Morphological Transformation for Efficient Chemodynamic Therapy

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. In this work, the preparation of 2D polyaniline/MoO 3–x (PANI/MoO 3–x ) superlattice nanosheets via intercalation-induced morphological transformation from MoO 3 nanobelts, as efficient Fenton-like reagents for chemodynamic therapy (CDT), is reported. Micrometer-long MoO 3 nanobelts are co-intercalated with Na + /H 2 O followed by the guest exchange with aniline monomer for in situ polymerization to obtain PANI/MoO 3–x nanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO 3 nanobelts to 2D PANI/MoO 3–x nanosheets along with the partial reduction of Mo 6+ to Mo 5+ , and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation-induced activation, the PANI/MoO 3–x nanosheets exhibit excellent Fenton-like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H 2 O 2 compared with the MoO 3 nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton-like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone-modified PANI/MoO 3–x nanosheets can function as Fenton-like reagents for highly efficient CDT to kill cancer cells and eradicate tumors.

2D materials↗
NASA NTRS2013

Modelling of Equilibrium Between Mantle and Core: Refractory, Volatile, and Highly Siderophile Elements

Siderophile elements have been used to constrain conditions of core formation and differentiation for the Earth, Mars and other differentiated bodies [1]. Recent models for the Earth have concluded that the mantle and core did not fully equilibrate and the siderophile element contents of the mantle can only be explained under conditions where the oxygen fugacity changes from low to high during accretion and the mantle and core do not fully equilibrate [2,3]. However these conclusions go against several physical and chemical constraints. First, calculations suggest that even with the composition of accreting material changing from reduced to oxidized over time, the fO2 defined by metal-silicate equilibrium does not change substantially, only by approximately 1 logfO2 unit [4]. An increase of more than 2 logfO2 units in mantle oxidation are required in models of [2,3]. Secondly, calculations also show that metallic impacting material will become deformed and sheared during accretion to a large body, such that it becomes emulsified to a fine scale that allows equilibrium at nearly all conditions except for possibly the length scale for giant impacts [5] (contrary to conclusions of [6]). Using new data for D(Mo) metal/silicate at high pressures, together with updated partitioning expressions for many other elements, we will show that metal-silicate equilibrium across a long span of Earth s accretion history may explain the concentrations of many siderophile elements in Earth's mantle. The modeling includes refractory elements Ni, Co, Mo, and W, as well as highly siderophile elements Au, Pd and Pt, and volatile elements Cd, In, Bi, Sb, Ge and As.

Righter, K.↗
DOE OSTI2020

Materials Data on Na4MnMo8O47 by Materials Project

Na4Mo8MnO43(O2)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional and consists of two oxygen molecules and one Na4Mo8MnO43 framework. In the Na4Mo8MnO43 framework, there are two inequivalent Na sites. In the first Na site, Na is bonded in a 4-coordinate geometry to four O atoms. There are a spread of Na–O bond distances ranging from 2.34–2.82 Å. In the second Na site, Na is bonded to seven O atoms to form distorted NaO7 pentagonal bipyramids that share a cornercorner with one MoO6 octahedra. The corner-sharing octahedral tilt angles are 12°. There are a spread of Na–O bond distances ranging from 2.29–2.86 Å. There are four inequivalent Mo sites. In the first Mo site, Mo is bonded to six O atoms to form distorted MoO6 octahedra that share a cornercorner with one NaO7 pentagonal bipyramid. There are a spread of Mo–O bond distances ranging from 1.72–2.21 Å. In the second Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.74–2.40 Å. In the third Mo site, Mo is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.73–2.40 Å. In the fourth Mo site, Mo is bonded in a 5-coordinate geometry to six O atoms. There are a spread of Mo–O bond distances ranging from 1.71–2.64 Å. Mn is bonded in a square co-planar geometry to four O atoms. There is two shorter (1.71 Å) and two longer (1.95 Å) Mn–O bond length. There are twenty-two inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the second O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the third O site, O is bonded in a linear geometry to one Na and one Mo atom. In the fourth O site, O is bonded in a water-like geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the fifth O site, O is bonded in a bent 150 degrees geometry to one Na and one Mo atom. In the sixth O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the seventh O site, O is bonded in a 3-coordinate geometry to three Mo atoms. In the eighth O site, O is bonded in a single-bond geometry to one Mo atom. In the ninth O site, O is bonded in a distorted L-shaped geometry to one Na and one O atom. The O–O bond length is 1.34 Å. In the tenth O site, O is bonded in a bent 120 degrees geometry to one Na and one O atom. The O–O bond length is 1.23 Å. In the eleventh O site, O is bonded in a bent 120 degrees geometry to two Mo atoms. In the twelfth O site, O is bonded in a single-bond geometry to one O atom. In the thirteenth O site, O is bonded in a linear geometry to one Mo and one Mn atom. In the fourteenth O site, O is bonded in a bent 150 degrees geometry to one Na and one Mo atom. In the fifteenth O site, O is bonded in a distorted rectangular see-saw-like geometry to four Mo atoms. In the sixteenth O site, O is bonded in a 2-coordinate geometry to one Na and one Mo atom. In the seventeenth O site, O is bonded in a single-bond geometry to one O atom. In the eighteenth O site, O is bonded in a 2-coordinate geometry to one Mo and one O atom. In the nineteenth O site, O is bonded in a bent 150 degrees geometry to two Na atoms. In the twentieth O site, O is bonded in a 3-coordinate geometry to three Mo atoms. In the twenty-first O site, O is bonded in a linear geometry to two equivalent Mo atoms. In the twenty-second O site, O is bonded in a distorted single-bond geometry to one Na and one Mn atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Sr 2 Fe 2–X Mo X O 6 double perovskites as electrocatalysts for oxidative dehydrogenation of ethane: Effect of B-site stoichiometry

The oxidative dehydrogenation of ethane (ODHE) was investigated using a solid oxide electrocatalytic cell with Sr 2 Fe 2–X Mo X O 6–δ (SFM) double perovskite as the anode electrocatalyst. As shown in the XRD patterns, SFM perovskites maintained their cubic structure upon modifying the B-site ratios of Mo and Fe. Increasing the Mo content of the perovskite structure resulted in a lower water signal intensity at low temperatures in TPR profiles, indicative of moderate oxygen transport through the perovskite structure. Because Mo–O bonds are stronger than Fe–O bonds, the electrical conductivity of SFM perovskites decreased with increasing Mo content. When operated at 100 mA cm –2 , ODHE activity improved four times compared to open circuit voltage, resulting in 16.1% conversion of C 2 H 6 and 83.1% selectivity to C 2 H 4 . It has been demonstrated that oxygen ions provided by perovskite lattices were the key species involved in activating C 2 H 6 based on the in-situ DRIFTS experiments. In conclusion, the SFM perovskite with higher Mo content showed the highest conversion and selectivity due moderate oxygen ion mobility and fast desorption of C 2 H 4 .

25 ENERGY STORAGE↗
DOE OSTI2020

Materials Data on RbMo3Cl7 by Materials Project

RbMo3Cl7 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 6-coordinate geometry to six Cl1- atoms. There are a spread of Rb–Cl bond distances ranging from 3.34–3.42 Å. In the second Rb1+ site, Rb1+ is bonded in a distorted square co-planar geometry to four equivalent Cl1- atoms. There are two shorter (3.17 Å) and two longer (3.27 Å) Rb–Cl bond lengths. There are three inequivalent Mo2+ sites. In the first Mo2+ site, Mo2+ is bonded to five Cl1- atoms to form edge-sharing MoCl5 square pyramids. There are a spread of Mo–Cl bond distances ranging from 2.44–2.50 Å. In the second Mo2+ site, Mo2+ is bonded to five Cl1- atoms to form edge-sharing MoCl5 square pyramids. There are a spread of Mo–Cl bond distances ranging from 2.47–2.51 Å. In the third Mo2+ site, Mo2+ is bonded to five Cl1- atoms to form edge-sharing MoCl5 square pyramids. There are three shorter (2.49 Å) and two longer (2.50 Å) Mo–Cl bond lengths. There are seven inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 3-coordinate geometry to three Mo2+ atoms. In the second Cl1- site, Cl1- is bonded in a distorted trigonal non-coplanar geometry to two equivalent Rb1+ and one Mo2+ atom. In the third Cl1- site, Cl1- is bonded in a 4-coordinate geometry to three Mo2+ atoms. In the fourth Cl1- site, Cl1- is bonded in a 6-coordinate geometry to three Mo2+ atoms. In the fifth Cl1- site, Cl1- is bonded in a 3-coordinate geometry to three Mo2+ atoms. In the sixth Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Rb1+ and one Mo2+ atom. In the seventh Cl1- site, Cl1- is bonded in a 3-coordinate geometry to two equivalent Rb1+ and one Mo2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Deliberate Construction of Polyoxoniobates Exploiting the Carbonate Ligand

Abstract Polyoxometalates (POMs, metals=V V , Nb V , Ta V , Mo VI , W VI ) are molecular metal oxides that can be isolated without capping ligands. The high negative charge of polyoxoniobates (PONb) provides strong interactions with heterocations, advantageous for electrostatic assembly of modular materials. In four single‐crystal X‐ray structures, we demonstrate that carbonate combined with the very reactive decaniobate [Nb 10 O 28 ] 6− reassembles into a new decaniobate, [Nb 10 O 25 (CO 3 ) 6 ] 12− , featuring three carbonate‐ligated Nb‐polyhedra. These Nb‐sites can be replaced by heterometals (lanthanides), and the tridentate carbonate can serve as an anchor point to build niobate‐frameworks. Small‐angle X‐ray scattering and two additional X‐ray structures reveal that the reaction pathway proceeds through a Nb 24 ‐PONb intermediate, and the obtained PONb (with or without carbonate) is counterion, temperature, and solvent‐dependent (water or mixed water‐methanol). This provides an uncommon level of control for PONb chemistry.

Amiri, Mehran↗
DOE OSTI2024

Elemental profiling and genomewide association studies reveal genomic variants modulating ionomic composition in Populus trichocarpa leaves

Samples were collected from a population of 1,089 black cottonwood genotypes (P. trichocarpa) assembled from native stands to encompass the central portion of the natural range of the species, stretching from 38.8° to 54.3° N Q13 latitude from California, USA, to British Columbia, Canada. Establishment of the common garden, growth conditions, and site maintenance have been described by Muchero et al (2015). In this study, leaf samples for ionomic profiling were collected from 4-year-old trees, during the growing season, in July 2012, from a field located in Clatskanie, Oregon, USA (46°6′11″N 123°12′13″W). The field site was located in a protected alluvial floodplain containing a uniform Wauna-Locoda silt loam soil area characterized by an acidic pH, in Columbia County, Oregon. A subset of 584 out of the 1,089 P. trichocarpa genotypes were represented in this sampling. These genotypes were randomly selected to represent the geographical distribution of the population. A single fully mature (LPI 7-9) leaf on the south side of the tree exposed to full sunlight conditions was removed from the tree within a 6-hour window centering on solar noon and immediately frozen under dry ice before processing. Leaf samples of 584 P. trichocarpa genotypes were finely ground to 40 mm particle size using a mortar and pestle, and ionomic composition was analyzed using ICP-MS. In total, 20 elements were profiled, including aluminum (Al27), arsenic (As75), boron (B11), cadmium (Cd111), calcium (Ca43), cobalt (Co), copper (Cu), iron (Fe57), magnesium (Mg25), manganese (Mn55), molybdenum (Mo), nickel (Ni60), phosphorus (P31), potassium (K39), rubidium (Rb85), selenium (Se82), sodium (Na23), strontium (Sr88), sulfur (S34), and zinc (Zn66), following a protocol established by Ziegler et al. (2013). For each sample, 75mg of powder was digested overnight in 2.5 mL HNO3 containing 20 parts per billion (ppb) indium as an internal standard, following the protocol described in Ziegler et al. (2013). Following a dilution, concentration of the 20 elements was measured using an Elan 6000 DRC-e mass spectrometer (Perkin-Elmer SCIEX) connected to a PFA microflow nebulizer (Elemental Scientific) and Apex HF desolvator (Elemental Scientific). One measurement per sample per genotype was done. For subsequent analyses, the quantifications were converted to total element concentration.

CBI ionomics, GWAS, plasma-mass spectrometry, neut↗
DOE OSTI2020

Materials Data on Ca2MoO5 by Materials Project

Ca2MoO5 crystallizes in the orthorhombic Ima2 space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.30–2.66 Å. Mo6+ is bonded to six O2- atoms to form distorted corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Mo–O bond distances ranging from 1.84–2.24 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a square co-planar geometry to four equivalent Ca2+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Mo6+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

High-yield growth kinetics and spatial mapping of single-walled carbon nanotube forests at wafer scale

Emerging commercial applications of vertically aligned, single-walled carbon nanotube (SWCNT) “forests” require synthesis that minimizes nanotube diameter while maximizing number density across substrate areas exceeding centimeter scale. To address this need, we synthesized SWCNT forests on full silicon wafers with notable reproducibility and uniformity, and co-optimized growth for small diameters and high densities across large areas to access new territory in this 3D parameter space. We mapped the spatial uniformity of key structural features using Raman microscopy, synchrotron X-ray scattering, and Rutherford backscattering spectrometry. Low C 2 H 2 flux over sub-nm Fe/Mo catalysts produced small-diameter SWCNTs (2.1 nm) at high number densities (2.26 × 10 12 cm -2 ) on wafers up to 6 in. Although removing Mo resulted in larger SWCNT diameters and lower densities (<0.7 × 10 12 cm -2 ), mass conversion rates from C 2 H 2 to SWCNT product were high and remarkably invariant for catalyst compositions and densities (i.e., 47.7% or 1.30 × 10 6 % g-catalyst -1 on 4-in. wafers). These carbon conversion efficiencies far exceed typical benchtop reactors and are on par with the best reported literature values. Our detailed elucidation of correlations among structural characteristics within this resource-efficient process is expected to guide future scale-up efforts of SWCNT forest growth beyond wafer scale.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The [M 6 (S 2 C 2 Ph 2 ) 6 ] (M = Ni, Pd, Pt) Series: Multielectron Reservoirs That Sustain Ligand-Based Oxidations and Metal-Based Reductions

A complete [M 6 (S 2 C 2 R 2 ) 6 ] series (M = Ni (1), Pd (2), Pt (3); R = Ph), the rarest variety among homoleptic dithiolene transition-metal compounds, has been prepared by reaction between [M(S 2 C 2 Ph 2 ) 2 ] and a M 0 source. The platinum member of this set is the first of its type. Diffraction-quality crystals, grown with high reproducibility by evaporation from PhNO 2 solutions, reveal fully reduced [Ph 2 C 2 S 2 ] 2– dianions and an octahedral M 6 core that is reduced to C 2 symmetry by the fusion of a mononuclear D 2h [M(S 2 C 2 Ph 2 ) 2 ] fragment upon a C 4 -symmetric base. The [Ni 6 (S 2 C 2 Ph 2 ) 2 ] 1– monoanion, prepared by Cp* 2 Co reduction, shows only modest structural differences from its neutral counterpart. In CH 2 Cl 2 , 1 and 2 can undergo two reductions and an oxidation, while 3 sustains two reductions and two oxidations. In benzonitrile, 1 sustains three reversible oxidations at potentials that are shifted appreciably to less positive values. The cathodic processes are shown by density functional theory (DFT) calculations to involve an MO largely of metal–sulfur composition that has contributions throughout the C 4 -symmetric pentametallic base of the assembly, while the oxidations are largely ligand-based and confined to the monometallic [M(S 2 C 2 Ph 2 ) 2 ] cap. The absorption spectra are marked by multiple overlapping bands that produce a continuous, tapering absorption profile of unresolved shoulders and swells.

Ligands↗
DOE OSTI2020

Materials Data on Na3Mo2N5 by Materials Project

Na3Mo2N5 is Chalcostibite-like structured and crystallizes in the tetragonal I4_1 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of Na–N bond distances ranging from 2.48–2.71 Å. In the second Na1+ site, Na1+ is bonded in a distorted trigonal non-coplanar geometry to three N3- atoms. There are a spread of Na–N bond distances ranging from 2.34–2.59 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of Na–N bond distances ranging from 2.54–2.93 Å. In the fourth Na1+ site, Na1+ is bonded in a square co-planar geometry to four N3- atoms. There are two shorter (2.35 Å) and two longer (2.39 Å) Na–N bond lengths. There are two inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded to four N3- atoms to form corner-sharing MoN4 tetrahedra. There are a spread of Mo–N bond distances ranging from 1.75–1.97 Å. In the second Mo6+ site, Mo6+ is bonded to four N3- atoms to form corner-sharing MoN4 tetrahedra. There are a spread of Mo–N bond distances ranging from 1.76–1.94 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded in a rectangular see-saw-like geometry to three Na1+ and one Mo6+ atom. In the second N3- site, N3- is bonded to four Na1+ and one Mo6+ atom to form distorted NNa4Mo trigonal bipyramids that share corners with two equivalent NNa4Mo trigonal bipyramids, corners with three equivalent NNa2Mo2 trigonal pyramids, and an edgeedge with one NNa4Mo trigonal bipyramid. In the third N3- site, N3- is bonded in a 2-coordinate geometry to two Na1+ and two equivalent Mo6+ atoms. In the fourth N3- site, N3- is bonded in a 4-coordinate geometry to two Na1+ and two equivalent Mo6+ atoms. In the fifth N3- site, N3- is bonded to two Na1+ and two Mo6+ atoms to form distorted NNa2Mo2 trigonal pyramids that share corners with three equivalent NNa4Mo trigonal bipyramids and a cornercorner with one NNa2Mo2 trigonal pyramid.

36 MATERIALS SCIENCE↗