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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

A Cautionary Tale: Failure of the Valence CASSCF to Describe the Hallmark of Hydrogen Bonding

Valence CASSCF (vCAS) calculations for the hydrogen-bonded (H2O)2, (HF)2, and HF–H2O dimers fail to predict the lengthening of the hydrogen donor bond and the corresponding red shift in the donor bond vibrational stretching frequency. Analysis of the active orbitals in the vCAS calculation reveals that one of the weakly occupied orbitals in each dimer is used to correlate the electrons in the acceptor lone pairs rather than those in the donor bonding orbitals. This has significant implications for subsequent treatments of the dynamical correlation that are based on the vCAS wavefunction.

Nguyen, Long H.↗
DOE OSTI2020

Isolating the Contributions of Specific Network Sites to the Diffuse Vibrational Spectrum of Interfacial Water with Isotopomer-Selective Spectroscopy of Cold Clusters

Decoding the structural information contained in the interfacial vibrational spectrum of water requires understanding how the spectral signatures of individual water molecules respond to their local hydrogen bonding environments. In this study, we isolated the contributions for the five classes of sites that differ according to the number of donor (D) and acceptor (A) hydrogen bonds that characterize each site. These patterns were measured by exploiting the unique properties of the water cluster cage structures formed in the gas phase upon hydration of a series of cations M+·(H2O)n (M = Li, Na, Cs, NH4, CH3NH3, H3O, and n = 5, 20-22). This selection of ions was chosen to systematically express the A, AD, AAD, ADD, and AADD hydrogen bonding motifs. The spectral signatures of each site were measured using two-color, IR-IR isotopomer-selective photofragmentation vibrational spectroscopy of the cryogenically cooled, mass selected cluster ions in which a single intact H2O is introduced without isotopic scrambling, an important advantage afforded by the cluster regime. The resulting patterns provide an unprecedented picture of the intrinsic line shapes and spectral complexities associated with excitation of the individual OH groups, as well as the correlation between the frequencies of the two OH groups on the same water molecule, as a function of network site. The properties of the surrounding water network that govern this frequency map are evaluated by dissecting electronic structure calculations that explore how changes in the nearby network structures, both within and beyond the first hydration shell, affect the local frequency of an OH oscillator. The qualitative trends are recovered with a simple model that correlates the OH frequency with the network-modulated local electron density in the center of the OH bond.

Yang, Nan↗
DOE OSTI2020

Observation of molecular hydrogen produced from bridging hydroxyls on anatase TiO2(101)

Anatase TiO2 is used extensively in a wide range of catalytic and photocatalytic processes and is a promising catalyst for hydrogen production. Here, we show that molecular hydrogen was produced from bridging hydroxyls, HOb, on the (101) surface of single crystal anatase (a-TiO2(101)). Electron bombardment at 30 K produced bridging oxygen vacancies in the surface. Deuterated bridging hydroxyls, DOb, were subsequently formed via dissociation of adsorbed D2O and confirmed by infrared reflection-absorption spectroscopy. During temperature programmed desorption (TPD) spectroscopy, D2 desorption was observed at 520 K. Density functional theory calculations show that both H2 and H2O production from HOb are endothermic at 0 K on a-TiO2(101), but H2 (H2O) desorption is entropically driven above 230 K (800 K). The calculated activation barrier for H2 desorption is 1.40 eV, which is similar to the desorption energy obtained from analysis of the D2 TPD spectra. The H2 desorption likely proceeds in two steps: H atom diffusion on the surface and then recombination. The calculations indicate that diffusion of the hydrogen atoms into the subsurface could also be an important process. We thank Drs. Z. Dohnalek and R. Rousseau for stimulating discussions. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, & Biosciences and performed in EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle. We also acknowledge the WPI computational facilities for providing resources to perform the DFT studies.

Deskins, N A.↗
DOE OSTI2026

Aqueous electrolyte solutions with anion-bridged secondary solvation sheaths for highly efficient zinc metal batteries

Aqueous zinc metal batteries are low-cost electrochemical devices suitable for safe grid energy storage. However, water decomposition and Zn dendrite formation detrimentally affect their coulombic efficiency. Conventional aqueous electrolyte solutions, with a concentration around 1 M, are cost-effective and exhibit high bulk ionic conductivity but cannot form a stable solid electrolyte interphase. Water-in-salt and aqueous-organic hybrid electrolyte solutions can form robust solid electrolyte interphases, but they are not kinetically efficient and cost-effective. Here, to circumvent these issues, we design variously concentrated aqueous electrolyte solutions using several salts with different donor numbers to extend anion coordination into the secondary solvation sheath. We show that salt-derived anions with donor number > 18 enter the Zn2+ first solvation sheath, and ensure a strong binding energy between the Zn2+(H2O)5-anion nanometric clusters and water molecules in the secondary solvation sheath. In particular, 2 M aqueous electrolyte solutions containing fluorinated anions exhibit bulk ionic conductivities of 26-35 mS cm−1 at 25 °C and form a ZnF2-rich solid electrolyte interphase. When tested in Zn||NaV3O8·1.5H2O Swagelok cells, the best-performing electrolyte solution enables an average coulombic efficiency of 99.99% for 1,000 cycles at 1.5 mA cm−2, corresponding to an initial specific energy of 130 Wh kg−1 (based on the combined weight of the positive and negative electrodes).

25 ENERGY STORAGE↗
DOE OSTI2020

A large molecular cluster with high proton release capacity

We present a single molecular polyoxometalate cluster (K-41[(P2W12Nb6O62)(6){Mn-3(OH)(3)(H2O)(6)}(4){Mn3Na(H2O)(16)}]center dot 26H(2)O) with controllable release of a large number of protons (similar to 40 per molecule) in its aqueous solution upon addition of a base. The deprotonation/protonation process is reversible with the clusters remaining intact. This molecule can also absorb up to 11 protons per cluster when an acid, HCl, was added to its original aqueous solution. To the best of our knowledge, such large proton absorption/release capacity along with excellent stability is unprecedented.

Zhang, Dongdi↗
DOE OSTI2026

Water-enhanced bifunctional metal-acid catalyst for C=C bond hydrogenation

Water-assisted proton shuttling can promote hydrogenation of polar functional groups, and it is generally believed that such an effect can be hardly applied to hydrogenation of C═C bonds due to the latter's weak interaction with water. Here, we report density functional theory calculations and metadynamics simulations, through which we show a dynamic bifunctional metal–acid site that can be transformed, when interacting with water, into an active configuration for unexpected water-enhanced proton shuttling to C═C bonds. In particular, we investigated B(OH)3 anchored to a Ni catalyst for hydrogenation of cyclohexene in an organic solvent, which showed in experiments an increased rate by 100 times when adding a small amount of water. Metadynamics simulations suggest that a B(OH)3–H2O cluster can form on Ni(111), which promotes the proton transfer in the first hydrogenation step, while the second hydrogenation is still driven by metal-mediated direct H-transfer. The recovery process of B(OH)3–H2O also involves a proton shuttling step. We find that the boric species on the surface serves as an electron reservoir and carries the negative charge to balance the positive charge in the proton transfer steps. This work thus provides fundamental insights into this dynamic transformation process of the metal–acid interface, which can in principle be applied to many other bifunctional systems for hydrogenating non-polar unsaturated groups by engineering the interfacial charge separation.

Sun, Shoutian↗
DOE OSTI2022

Coupled Cluster Downfolding Methods: the effect of double commutator terms on the accuracy of ground-state energies

Downfolding coupled cluster (CC) techniques have recently been introduced into quantum chemistry as a tool for the dimensionality reduction of the many-body quantum problem. As opposed to earlier formulations in physics and chemistry based on the concept of effective Hamiltonians, the appearance of the downfolded Hamiltonians is a natural consequence of the single-reference exponential parametrization of the wave function. In this paper, we discuss the impact of higher-order terms originating in double commutators. In analogy to previous studies, we consider the case when only one- and two-body interactions are included in the downfolded Hamiltonians. We demonstrate the efficiency of the many-body expansions involving single and double commutators for the unitary extension of the downfolded Hamiltonians on the example of the beryllium atom, and bond-breaking processes in the Li2 and H2O molecules. For the H2O system, we also analyze energies obtained with downfolding procedures as functions of the active space size.

quantum computing, quantum algorithms, electronic ↗
DOE OSTI2023

Scalable generalized screening for high-order terms in the many-body expansion: Algorithm, open-source implementation, and demonstration

The many-body expansion lies at the heart of numerous fragment-based methods that are intended to sidestep the nonlinear scaling of ab initio quantum chemistry, making electronic structure calculations feasible in large systems. In principle, inclusion of higher-order n-body terms ought to improve the accuracy in a controllable way, but unfavorable combinatorics often defeats this in practice and applications with n ≥ 4 are rare. Here, we outline an algorithm to overcome this combinatorial bottleneck, based on a bottom-up approach to energy-based screening. This is implemented within a new open-source software application (“Fragme∩t”), which is integrated with a lightweight semi-empirical method that is used to cull subsystems, attenuating the combinatorial growth of higher-order terms in the graph that is used to manage the calculations. This facilitates applications of unprecedented size, and we report four-body calculations in (H2O)64 clusters that afford relative energies within 0.1 kcal/mol/monomer of the supersystem result using less than 10% of the unique subsystems. We also report n-body calculations in (H2O)20 clusters up to n = 8, at which point the expansion terminates naturally due to screening. These are the largest n-body calculations reported to date using ab initio electronic structure theory, and they confirm that high-order n-body terms are mostly artifacts of basis-set superposition error.

Chemistry↗
DOE OSTI2024

Convergent ab initio analysis of the multi-channel HOBr + H reaction

High-level potential energy surfaces for three reactions of hypobromous acid with atomic hydrogen were computed at the CCSDTQ/CBS//CCSDT(Q)/complete basis set level of theory. Focal point analysis was utilized to extrapolate energies and gradients for energetics and optimizations, respectively. The H attack at Br and subsequent Br–O cleavage were found to proceed barrierlessly. The slightly submerged transition state lies −0.2 kcal mol−1 lower in energy than the reactants and produces OH and HBr. The two other studied reaction paths are the radical substitution to produce H2O and Br with a 4.0 kcal mol−1 barrier and the abstraction at hydrogen to produce BrO and H2 with an 11.2 kcal mol−1 barrier. The final product energies lie −37.2, −67.9, and −7.3 kcal mol−1 lower in energy than reactants, HOBr + H, for the sets of products OH + HBr, H2O + Br, and H2 + BrO, respectively. Additive corrections computed for the final energetics, particularly the zero-point vibrational energies and spin–orbit corrections, significantly impacted the final stationary point energies, with corrections up to 6.2 kcal mol−1.

Chemistry↗
DOE OSTI2024

The Ecosystem as Super-Organ/ism, Revisited: Scaling Hydraulics to Forests under Climate Change

Synopsis Classic debates in community ecology focused on the complexities of considering an ecosystem as a super-organ or organism. New consideration of such perspectives could clarify mechanisms underlying the dynamics of forest carbon dioxide (CO2) uptake and water vapor loss, important for predicting and managing the future of Earth’s ecosystems and climate system. Here, we provide a rubric for considering ecosystem traits as aggregated, systemic, or emergent, i.e., representing the ecosystem as an aggregate of its individuals or as a metaphorical or literal super-organ or organism. We review recent approaches to scaling-up plant water relations (hydraulics) concepts developed for organs and organisms to enable and interpret measurements at ecosystem-level. We focus on three community-scale versions of water relations traits that have potential to provide mechanistic insight into climate change responses of forest CO2 and H2O gas exchange and productivity: leaf water potential (Ψcanopy), pressure volume curves (eco-PV), and hydraulic conductance (Keco). These analyses can reveal additional ecosystem-scale parameters analogous to those typically quantified for leaves or plants (e.g., wilting point and hydraulic vulnerability) that may act as thresholds in forest responses to drought, including growth cessation, mortality, and flammability. We unite these concepts in a novel framework to predict Ψcanopy and its approaching of critical thresholds during drought, using measurements of Keco and eco-PV curves. We thus delineate how the extension of water relations concepts from organ- and organism-scales can reveal the hydraulic constraints on the interaction of vegetation and climate and provide new mechanistic understanding and prediction of forest water use and productivity.

Zoology↗
DOE OSTI2024

Rehydrated glass embayments record the cooling of a Yellowstone ignimbrite

Abstract Hydration fronts penetrate 50–135 μm into glassy rhyolite embayments hosted in quartz crystals from the Mesa Falls Tuff in the Yellowstone Plateau volcanic field. The hydration fronts occur as steep enrichments that reach 2.4 ± 0.6 wt% H2O at the embayment opening, representing much higher values than interior concentrations of 0.9 ± 0.2 wt% H2O. Molecular water accounts for most of the water enrichment. Water speciation indicates the hydration fronts comprise absorbed meteoric water that modified the original magmatic composition of the rhyolitic glass. We used finite difference diffusion models to demonstrate that glass rehydration was likely produced over a few decades as the ignimbrite cooled. Such temperatures and time scales are consistent with rare firsthand observations of decadal hydrothermal systems associated with cooling ignimbrites at Mount Pinatubo (Philippines) and the Valley of Ten Thousand Smokes (Alaska).

Geology↗
DOE OSTI2020

Materials Data on CaPH5O6 by Materials Project

CaHPO4(H2O)2 crystallizes in the monoclinic Cc space group. The structure is two-dimensional and consists of two CaHPO4(H2O)2 sheets oriented in the (0, 1, 0) direction. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.85 Å. P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.53–1.62 Å. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the fourth H1+ site, H1+ is bonded in a distorted linear geometry to two O2- atoms. There is one shorter (1.02 Å) and one longer (1.63 Å) H–O bond length. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+, one P5+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one P5+, and one H1+ atom. In the sixth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H2CO by Materials Project

CH2O crystallizes in the orthorhombic P2_12_12_1 space group. The structure is two-dimensional and consists of two C ribbons oriented in the (1, 0, 0) direction and two H2O sheets oriented in the (0, 0, 1) direction. In each C ribbon, C2+ is bonded in a linear geometry to two equivalent C2+ atoms. Both C–C bond lengths are 1.29 Å. In each H2O sheet, there are two inequivalent H sites. In the first H site, H is bonded in a distorted bent 150 degrees geometry to two equivalent O2- atoms. There is one shorter (1.00 Å) and one longer (1.69 Å) H–O bond length. In the second H site, H is bonded in a distorted single-bond geometry to two equivalent O2- atoms. There is one shorter (1.00 Å) and one longer (1.87 Å) H–O bond length. O2- is bonded in a distorted water-like geometry to four H atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H5BrO2 by Materials Project

(H2O)2HBr crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one (H2O)2HBr sheet oriented in the (-1, 2, 0) direction. there are twenty inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.18 Å. In the second H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.08 Å) and one longer (1.42 Å) H–O bond length. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.02 Å. The H–Br bond length is 2.10 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.15 Å. In the fifth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.10 Å) and one longer (1.36 Å) H–O bond length. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.17 Å. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.03 Å. The H–Br bond length is 2.09 Å. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.17 Å. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.23 Å. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.01 Å. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.01 Å. The H–Br bond length is 2.20 Å. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifteenth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.11 Å) and one longer (1.34 Å) H–O bond length. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- and one Br1- atom. The H–O bond length is 1.00 Å. The H–Br bond length is 2.26 Å. In the twentieth H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.16 Å) and one longer (1.26 Å) H–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the second O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the fourth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to three H1+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three H1+ atoms. In the eighth O2- site, O2- is bonded in a trigonal planar geometry to three H1+ atoms. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 2-coordinate geometry to two H1+ atoms. In the second Br1- site, Br1- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. In the third Br1- site, Br1- is bonded in a 2-coordinate geometry to three H1+ atoms. In the fourth Br1- site, Br1- is bonded in a 1-coordinate geometry to one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ReH3O5 by Materials Project

H(ReO4)H2O crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of two H(ReO4)H2O clusters. Re7+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Re–O bond distances ranging from 1.74–1.79 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.09 Å) and one longer (1.36 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 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three H1+ atoms. In the second O2- site, O2- is bonded in a single-bond geometry to one Re7+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Re7+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one Re7+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one Re7+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuH16(ClO8)2 by Materials Project

Cu(H2O)6(H2O)2(ClO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two copper hexahydrate molecules, four water molecules, and four ClO4 clusters. In each ClO4 cluster, there are four inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.47 Å. In the second O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.49 Å. In the third O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.44 Å. In the fourth O site, O is bonded in a single-bond geometry to one Cl atom. The O–Cl bond length is 1.47 Å. Cl is bonded in a tetrahedral geometry to four O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2Mg3H48(NO5)12 by Materials Project

(Mg(H2O)6)3(La(NO3)6)2(H2O)6 is Brookite-derived structured and crystallizes in the trigonal R-3 space group. The structure is zero-dimensional and consists of nine magnesium;hexahydrate molecules, eighteen water molecules, and six La(NO3)6 clusters. In each La(NO3)6 cluster, La is bonded in a cuboctahedral geometry to twelve O atoms. There are a spread of La–O bond distances ranging from 2.67–2.71 Å. There are two inequivalent N sites. In the first N site, N is bonded in a trigonal planar geometry to three O atoms. There is one shorter (1.24 Å) and two longer (1.28 Å) N–O bond length. In the second N site, N is bonded in a trigonal planar geometry to three O atoms. There are a spread of N–O bond distances ranging from 1.24–1.29 Å. There are six inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to one La and one N atom. In the second O site, O is bonded in a distorted single-bond geometry to one La and one N atom. In the third O site, O is bonded in a single-bond geometry to one N atom. In the fourth O site, O is bonded in a distorted single-bond geometry to one La and one N atom. In the fifth O site, O is bonded in a distorted single-bond geometry to one La and one N atom. In the sixth O site, O is bonded in a single-bond geometry to one N atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mn3H24(O3F2)4 by Materials Project

Mn(H2O)6(MnH4(OF2)2)2(H2O)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one manganese hexahydrate molecule, two water molecules, and two MnH4(OF2)2 clusters. In each MnH4(OF2)2 cluster, Mn+2.67+ is bonded in an octahedral geometry to two O2- and four F1- atoms. There are one shorter (2.21 Å) and one longer (2.33 Å) Mn–O bond lengths. There are a spread of Mn–F bond distances ranging from 1.88–1.91 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Mn+2.67+ and two H1+ atoms. In the second O2- site, O2- is bonded in a distorted water-like geometry to one Mn+2.67+ and two H1+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to one Mn+2.67+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Mn+2.67+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to one Mn+2.67+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Mn+2.67+ atom.

36 MATERIALS SCIENCE↗