DOCSLIB.ORG

High-Throughput Identification of Electrides from All Known Inorganic

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
High-Throughput Identification of Electrides from All Known Inorganic Article Cite This: Chem. Mater. XXXX, XXX, XXX−XXX pubs.acs.org/cm High-Throughput Identification of Electrides from All Known Inorganic Materials Lee A. Burton, Francesco Ricci, Wei Chen, Gian-Marco Rignanese, and Geoffroy Hautier* Institute of Condensed Matter and Nanoscience, UniversitéCatholique de Louvain, 1348 Louvain-la-Neuve, Belgium *S Supporting Information ABSTRACT: In this paper, we present the results of a large- scale, high-throughput computational search for electrides among all known inorganic materials. Analyzing a database of density functional theory results on more than 60 000 compounds, we identify 65 new electride candidates and recover 4 already known. We report on all these candidates and discuss the structural and chemical factors leading to electride formation. Among these candidates, our work identifies the first partially filled 3d transition-metal-containing fi electrides Ba3CrN3 and Sr3CrN3, an unexpected nding that contravenes conventional chemistry. ■ INTRODUCTION large energy of a unbound electron.15 For example, the 2D 2+ 3− Electrides are rare ionic compounds in which an electron does electride Ca2N has two Ca cations and one N anion not occupy an atomic orbital but rather acts as an anion. Such (according to commonly held concepts of oxidation state). an electron is expected to behave differently from those The electropositive Ca cations wish to donate four electrons, occupying the valence state of standard materials, making but the anion can only accept three, leading to an excess electrides desirable as electron emitters,1 nonlinear optical electron occupying free space in the crystal structure, thereby switches,2 superconductors,3 battery anodes,4 and catalysts for satisfying all three criteria. The need for these three factors to combine adequately makes electrides a rare occurrence among applications ranging from compound synthesis to CO2 splitting.5,6 solid compounds with only a handful electrides known so far. Chemically independent electrons were first reported from Quantum-mechanical calculations have been essential in the salts of metal−ammonia solutions.7 Solid-state organic quest for new electrides. They are commonly used in electrides were reported in 1990 but were unstable at room conjunction with experimental characterization (e.g., catalytic temperature even in inert atmosphere.8 In 2012, a break- activity or transport measurements) to demonstrate the through came with the first inorganic electride stable at room electride nature of a material. By observing the localization temperature and in air: Ca Al O in the mayenite structure.9 of electrons resulting from computations in the density 12 14 32 functional theory (DFT) framework, one can determine if Downloaded via UNIV CATHOLIQUE DE LOUVAIN on October 22, 2018 at 14:10:08 (UTC). Now, various stable electrides are known. They are often See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles. fi the electrons occupy space away from a nuclei, the definition of classi ed according to the localization of the anionic electron 16,17 in the lattice: 0-dimensional (0D)10 when it resides in a cavity, an electride. Ab initio techniques have been used 11 extensively in the past to predict electride-like behavior in 1-dimensional (1D) when it is enclosed in a channel, and 2- 18−21 dimensional (2D)12 when it is confined to a layer. These high-pressure elements. However, no large-scale, broad compounds are now being tested in multiple industrial computationally driven search for electrides has yet been 13 performed among known, stable, inorganic compounds at applications from NH3 catalysis, to light emitting diode (LED) devices.14 As such, electride chemistry has become an ambient pressure. active field of solid-state chemistry and materials science with Here, we search for potential electrides among a large large efforts directed toward their discovery, synthesis, and database containing DFT electronic structure data on materials originating mainly from those experimentally reported in the characterization. 22 Several simple rules have been used to identify possible Inorganic Crystal Structure Database (ICSD). From this electride candidates. First, the structure must contain free database of more than 60 000 compounds, we identify 65 new space where the anionic electron can reside,8 be this a cavity, a potential electrides and recover 4 already known, without channel, or a layer. Second, a compound must have an excess electron to contribute to the lattice, as determined by the sum Received: June 15, 2018 of oxidation states of the components.15 Finally, the compound Revised: October 9, 2018 must contain a strongly donating cation to offset the naturally Published: October 10, 2018 © XXXX American Chemical Society A DOI: 10.1021/acs.chemmater.8b02526 Chem. Mater. XXXX, XXX, XXX−XXX Chemistry of Materials Article relying on any of the design principles associated with their NdGa, CaSi, SrSn, BaGe, SrGe, CaGe, BaSi, SrSi, and BaSn, usual discovery. We discuss the 3 most popular groups of which are orthorhombic with the space group Cmcm (No. 63). candidates, which incidentally form 0D, 1D, and 2D electrides. The structures consist of bonded atomic bilayers sandwiched Furthermore, we highlight what we believe to be the only between 2D free electron layers (see Figure 1) and are referred known instances of electrides containing a redox active fi element: Ba3CrN3 and Sr3CrN3 (signi cant as one would expect a redox active transition metal to accept the anionic electron). Finally, we re-evaluate the previously proposed guiding principles for electride formation in light of our large- scale screening. ■ METHODS Our computational screening began with the Materials Project,22 a database of 69 640 materials computed using the Vienna ab initio Simulation Package (VASP) using the GGA-PBE implementation of DFT.23,24 Of these, we exclude materials of just one component, i.e., elements, and those with a calculated energy above the convex hull of more than 24 meV per atom, which has been shown to be an accurate measure of stability in compounds.25 We focused on materials with Figure 1. Electron density around the Fermi level for the CrB class the Fermi level (EF) crossing several bands of the compounds that have calculated band structures, i.e., metals. The first screening step candidates clearly indicative of a 2D electride material (NdGa in this was using the projections on atomic orbitals for the eigenstates case). around EF in a range of 0.01 eV. If these projections summed to less than 50% of the total electrons present, we expect a high chance for to as CrB-type structures in the original reports. Of these 11, 8 the electrons to occupy nonatomic sites and, thus, be an electride. In a are II−IV compounds, complying with the principle of second step, we performed a Bader charge analysis to identify electron including an electropositive element (group II) in the distributions with a relative charge of at least 0.1 located 2.2 Å or 26−28 compound. However, the rule of an excess electron from the more away from the nearest atom, within 0.2 eV of the EF for a 2000 k points per Å−3 resolution calculation,29 similar to alternate oxidation states does not apply. To the knowledge of the work in the field.30,31 The parameters were chosen to return as few authors, these compounds have never been considered candidates as possible while still recovering the four known electrides electrides but show 2D behavior similar to that of the well- 32 33 16 34 Ca2N, Y2C, Y5Si3, and LaH2, identifying 69 nonelemental studied Ca2N. “ ” candidates in total. We note that only as-is electrides will be found Of the 69 systems, 9 adopt the so-called Mn5Si3 structure fi through our approach and that we do not expect to nd mayenite, for type, including the known electride Y5Si3, which is reported to instance, which requires a chemical treatment (oxygen deintercala- 16 35 be chemically stable even in the presence of moisture. These tion) to produce its electride form. are Ba As ,CaSb ,NdGe ,SrAs ,YSi ,SrSb ,SrBi , The quasiparticle self-consistent GW (QSGW) calculations were 5 3 5 3 5 3 5 3 5 3 5 3 5 3 36 Ba5Bi3, and Ba5Sb3, all of which are hexagonal with the space performed using ABINIT. The dielectric function and quasiparticle − self-energies are evaluated on a 4 × 4 × 6 k-point mesh and with 1000 group P63/mcm (No. 193). Of the 9 compounds, 7 are II V bands (see Supporting Information for the convergence study). The compounds. In the unit cells, 3 of 5 cations sit at the center of energy cutoff for the dielectric function is 160 eV. The semicore sp face-sharing octahedra, while the remaining 2 coordinate electrons are included among valence for the Ba, Sr, and Cr atoms.37 toward a 1D channel populated by the anionic electron, see In addition to all the valence states, we include 80 unoccupied states Figure 2. for which the wave functions and eigenvalues are iterated to self- consistency. The virtue of QSGW (compared to one-shot G0W0)is that when self-consistency is reached, all remnants of the DFT starting point are eliminated. ■ RESULTS Our screening begins with the Materials Project database, which includes DFT electronic structure data for a large set of known materials. By analyzing the charge density around the Fermi level for all stable metallic materials within this database, we can detect the compounds presenting the off-nuclei electron localization characteristic of an electride (see Methods). Our search identifies 69 compounds with 4 32 33 previously reported electrides among them (Ca2N, Y2C, Figure 2. Structure and electron density channel (perpendicular to Y Si ,16 and LaH 34). We stress that, contrary to previous 5 3 2 the page) for the Mn5Si3 compounds (Ba5As3 in this case).
Load more

Recommended publications
  • Applicability of Electride Materials for Hollow Cathodes
    Applicability of electride materials for hollow cathodes IEPC-2019-A-604 Presented at the 36th International Electric Propulsion Conference University of Vienna, Austria September 15-20, 2019 Malina Reitemeyer∗, Daniel Zsch¨atzschy, Kristof Holstez, Limei Chenx and Peter J. Klar{ Institute of Experimental Physics I, Justus-Liebig-University Giessen Heinrich-Buff-Ring 16, 35392 Giessen, Germany Due to its low work function, the electride C12A7:e− emits electrons at significantly lower temperatures than state of the art neutralizer materials and is a promising insert candidate for a cold-cathode design. The material's electron density and, therefore, also the emission properties are influenced by the quality of the fabrication process and surface conditions. Understanding and influencing them subsequently, is part of our current re- search. In this work, the emission characteristics of C12A7:e− as a function of the applied temperature and voltage are presented. The work function was measured as 0.52 eV ± 0.03 eV. In addition, both an intrinsic electride sample and an oxidized sample are char- acterized by Raman spectroscopy. The Raman spectra reveal an electron density of the order of 1019cm−3 to 1020cm−3 for the electride and correspond to the spectrum of the ion conducting C12A7:O2− in case of the oxidized sample. Nomenclature AG = general Richardson constant d = distance between anode and cathode e = elementary charge E = electric field I = extracted current IR = zero field current J = extracted current density JR = zero field current density
    [Show full text]
  • Interplay of Anionic Quasi-Atom and Interstitial Point Defects In
    Interplay of anionic quasi-atom and interstitial point defects in electrides: abnormal interstice occupation and colossal charge state of point defects in dense FCC-lithium L. Zhang,† Q. Wu,† S. Li,† Y. Sun,† X. Yan,†, ‡ Y. Chen,+ and Hua Y. Geng*, †, § †National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, P.O. Box 919-102, Mianyang, Sichuan 621900, P.R. China ‡Jiangxi University of Science and Technology, Ganzhou, Jiangxi 341000, P.R. China +Fracture and Reliability Research Institute, School of Engineering, Tohoku University 6-6-01 Aramakiaoba, Aoba-ku, Sendai, 980-8579, Japan §Center for Applied Physics and Technology, HEDPS, and College of Engineering, Peking University, Beijing 100871, P.R. China Abstract: Electrides are an emerging class of materials with highly-localized electrons in the interstices of a crystal that behave as anions. The presence of these unusual interstitial quasi-atom (ISQ) electrons leads to interesting physical and chemical properties, and wide potential applications for this new class of materials. Crystal defects often have a crucial influence on the properties of materials. Introducing impurities has been proved to be an effective approach to improve the properties of a material and to expand its applications. However, the interactions between the anionic ISQs and the crystal defects in electrides are as yet unknown. Here, dense FCC-Li was employed as an archetype to explore the interplay between anionic ISQs and interstitial impurity atoms in this electride. This work reveals a strong coupling among the interstitial impurity atoms, the ISQs, and the matrix Li atoms near to the defects.
    [Show full text]
  • Electride Characteristics of M2( 5-E5)
    Electride Characteristics of M2(h5-E5)2 (M= Be, Mg; E= Sb5-) Prasenjit Das IIT Kharagpur: Indian Institute of Technology Kharagpur Pratim Kumar Chattaraj ( [email protected] ) IIT Kharagpur Research Article Keywords: Electride, Binuclear Sandwich Compound, Non-nuclear attractor (NNA), Electron localization function (ELF) basin, NLO properties Posted Date: February 24th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-232917/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Version of Record: A version of this preprint was published at Structural Chemistry on April 23rd, 2021. See the published version at https://doi.org/10.1007/s11224-021-01783-1. 5 - Electride Characteristics of M2( -E5)2 (M= Be, Mg; E= Sb5 ) Prasenjit Das,a Pratim Kumar Chattaraja,b,* a Department of Chemistry, Indian Institute of Technology Kharagpur, Kharagpur 721302, India b Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India *E-mail: [email protected] (PKC) Abstract 5 Ab initio computation is performed on the binuclear sandwich complexes, M2( -Sb5)2. Eclipsed 5 - and staggered conformations are generated due to the mode of binding by Sb5 ligand with the alkaline earth metals (Be and Mg metals). The complexes are thermodynamically stable at room temperature. The electron density descriptors and the natural bond orbital (NBO) analysis 5 5 confirmed the covalent nature of the M-M bond. Both Be2( -Sb5)2 and Mg2( -Sb5)2 complexes have one non-nuclear attractor (NNA) at the center of the M-M bond which is predicted and confirmed by the electron density analysis.
    [Show full text]
  • A New Electride with Partially Filled D-Shells Padtaraporn Chanhom1,2, Kevin E
    Sr3CrN3: a new electride with partially filled d-shells Padtaraporn Chanhom1,2, Kevin E. Fritz1, Lee Burton3, Jan Kloppenburg3, Yaroslav Filinchuk3, Anatol- yi Senyshin4, Maoyu Wang5, Zhenxing Feng5, Numpon Insin2, Jin Suntivich1,6, Geoffroy Hautier3 1 Materials Science and Engineering Department, Cornell University, Ithaca, NY 14850, USA 2 Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand 3 Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Louvain-la-Neuve 1348, Belgium 4 Heinz Maier-Leibnitz Zentrum, Technische Universität München, 85748 Garching, Germany 5 School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvalis, OR 97331 USA 6 Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14850, USA ABSTRACT: Electrides are ionic crystals in which the electrons prefer to occupy free space, serving as anions. Because the electrons prefer to be in the pockets, channels, or layers to the atomic orbitals around the nuclei, it has been challenging to find electrides with partially filled d-shells, since an unoc- cupied d-shell provides an energetically favourable location for the electrons to occupy. We recently predicted the existence of electrides with partially filled d-shells using high-throughput computational screening. Here, we provide an experimental support using X-ray absorption spectroscopy and X-ray and neutron diffraction to show that Sr3CrN3 is indeed an electride despite its partial d-shell configura- tion. Our findings indicate that Sr3CrN3 is the first known electride with a partially filled d-shell, in agreement with theory, which significantly broadens the criteria for the search for new electride materi- als.
    [Show full text]
  • Acid-Durable Electride with Layered Ruthenium for Ammonia Synthesis: Boosting the Activity Via Cite This: Chem
    Chemical Science View Article Online EDGE ARTICLE View Journal | View Issue Acid-durable electride with layered ruthenium for ammonia synthesis: boosting the activity via Cite this: Chem. Sci.,2019,10,5712 † All publication charges for this article selective etching have been paid for by the Royal Society a a b a a of Chemistry Jiang Li, ‡ Jiazhen Wu, ‡ Haiyun Wang, Yangfan Lu, Tiannan Ye, Masato Sasase, a Xiaojun Wu, *b Masaaki Kitano, *a Takeshi Inoshita a and Hideo Hosono *a Ruthenium (Ru) loaded catalysts are of significant interest for ammonia synthesis under mild reaction conditions. The B5 sites have been reported as the active sites for ammonia formation, i.e., Ru with other coordinations were inactive, which has limited the utilization efficiency of Ru metal. The implantation of Ru into intermetallic compounds is considered to be a promising approach to tune the catalytic activity and utilization efficiency of Ru. Here we report an acid-durable electride, LnRuSi (Ln ¼ La, Ce, Pr and Nd), as a B5-site-free Ru catalyst. The active Ru plane with a negative charge is selectively exposed by Creative Commons Attribution-NonCommercial 3.0 Unported Licence. chemical etching using disodium dihydrogen ethylenediaminetetraacetate (EDTA-2Na) acid, which leads to 2–4-fold enhancement in the ammonia formation rate compared with that of the original catalyst. The turnover frequency (TOF) of LnRuSi is estimated to be approximately 0.06 sÀ1, which is 600 times Received 29th March 2019 higher than that of pure Ru powder. Density functional theory (DFT) calculations revealed that the Accepted 3rd May 2019 dissociation of N2 occurs easily on the exposed Ru plane of LaRuSi.
    [Show full text]
  • Electrides and Alkalides - Comparison with Metal Solutions J
    ELECTRIDES AND ALKALIDES - COMPARISON WITH METAL SOLUTIONS J. Dye To cite this version: J. Dye. ELECTRIDES AND ALKALIDES - COMPARISON WITH METAL SOLUTIONS. Journal de Physique IV Proceedings, EDP Sciences, 1991, 01 (C5), pp.C5-259-C5-282. 10.1051/jp4:1991531. jpa-00250655 HAL Id: jpa-00250655 https://hal.archives-ouvertes.fr/jpa-00250655 Submitted on 1 Jan 1991 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL DE PHYSfQUE IV Colloque C5, supplkment au Journal de Physique I, Vol. 1, dkcembre 1991 ELECTRIDES AND ALKALIDES - COMPARISON WITH METAL SOLUTIONS J.L. DYE Department of Chemistry and Centerfor Fundamental Matefials Research, Michigan State University, East Lansing, Michigan 48824, USA. Abstract - The similarities between species in ammonia, amine and ether solutions of the alkali metals and in crystalline alkalides and electrides is striking. In solution we can identify the species M+,olv, e-,,lV, M-, M+-e-, "e2"', and at high concentrations, e-conduction. In alkalides, electrides and mixed systems, species analogous to each of these can be found, in addition to alkali metal anion dimers, M=,olv, and chains, (M"-)". Since the last Colloque Weyl we have determined the crystal structures and properties of 30 alkalides and 4 electrides.
    [Show full text]
  • Effect of Substituents of Cerium Pyrazolates and Pyrrolates on Carbon Dioxide Activation
    molecules Article Effect of Substituents of Cerium Pyrazolates and Pyrrolates on Carbon Dioxide Activation Uwe Bayer, Adrian Jenner, Jonas Riedmaier, Cäcilia Maichle-Mössmer and Reiner Anwander * Institute of Inorganic Chemistry, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany; [email protected] (U.B.); [email protected] (A.J.); [email protected] (J.R.); [email protected] (C.M.-M.) * Correspondence: [email protected] Abstract: Homoleptic ceric pyrazolates (pz) Ce(RR’pz)4 (R = R’ = tBu; R = R’ = Ph; R = tBu, R’ = Me) were synthesized by the protonolysis reaction of Ce[N(SiHMe2)2]4 with the corresponding pyrazole derivative. The resulting complexes were investigated in their reactivity toward CO2, revealing a significant influence of the bulkiness of the substituents on the pyrazolato ligands. The efficiency of the CO2 insertion was found to increase in the order of tBu2pz < Ph2pz < tBuMepz < Me2pz. For comparison, the pyrrole-based ate complexes [Ce2(pyr)6(m-pyr)2(thf)2][Li(thf)4]2 (pyr = pyrro- lato) and [Ce(cbz)4(thf)2][Li(thf)4] (cbz = carbazolato) were obtained via protonolysis of the cerous ate complex Ce[N(SiHMe2)2]4Li(thf) with pyrrole and carbazole, respectively. Treatment of the pyrrolate/carbazolate complexes with CO2 seemed promising, but any reversibility could not be observed. Keywords: cerium; pyrazoles; pyrroles; carbazoles; carbon dioxide Citation: Bayer, U.; Jenner, A.; Riedmaier, J.; Maichle-Mössmer, C.; Anwander, R. Effect of Substituents of 1. Introduction Cerium Pyrazolates and Pyrrolates on Rare-earth–metal complexes are capable of efficiently activating carbonylic com- Carbon Dioxide Activation.
    [Show full text]
  • Supporting Information for Angew. Chem. Int. Ed. 200460478 © Wiley-VCH 2004
    Supporting Information for Angew. Chem. Int. Ed. 200460478 © Wiley-VCH 2004 69451 Weinheim, Germany [Yb3N(Dpa)6][Yb(Dpa)3], das erste molekulare Nitrid eines Selten-Erd- ** Elementes mit einer Yb3N-Einheit Catharina C. Quitmann und Klaus Müller-Buschbaum* ** − (Dpa = dipyridylamide anion, (C5H4N)2N ) Experimental As described in the manuscript, [Yb3N(Dpa)6][Yb(Dpa)3] (Dpa = dipyridylamide anion − (C5H4N)2N ) is obtained via a combination of the low temperature oxidation of ytterbium metal with 2,2’-dipyridylamide in liquid ammonia and a subsequent temperature program in an evacuated ampoule. Liquid ammonia is capable of solvating electrons and already dissolves both europium and ytterbium at normal pressure. The formation of an electride is only an intermediate, which is followed by the immediate reaction with the amine ligand, producing hydrogen. This process is accompanied by a colour change of the solution from deep blue to green and yellow. It has to be stressed, that the crystalline product obtained from the temper process is not necessarily the initial reaction product obtained from liquid ammonia. Instead it is most likely that homoleptic ammonia complexes of ytterbium are formed first, which decompose upon the removal of ammonia. Furthermore non-coordinating ammonia solvate molecules will be released from the product at this stage. In contrast the nitride ion centring the triangular Yb3N 3- unit is a result of the ammonolysis of NH3 to N and survives both the removal of ammonia as well as the subsequent heating in evacuated ampoules, which is necessary to obtain a crystalline product suitable for the single crystal X-ray diffraction.
    [Show full text]
  • Ferromagnetic Quasi-Atomic Electrons in Two-Dimensional Electride
    ARTICLE https://doi.org/10.1038/s41467-020-15253-5 OPEN Ferromagnetic quasi-atomic electrons in two-dimensional electride Seung Yong Lee 1,2,10, Jae-Yeol Hwang 1,3,10, Jongho Park 1,2, Chandani N. Nandadasa 4, Younghak Kim5, Joonho Bang1, Kimoon Lee6, Kyu Hyoung Lee 7, Yunwei Zhang 8, Yanming Ma8, Hideo Hosono9, ✉ Young Hee Lee 2, Seong-Gon Kim 4 & Sung Wng Kim1,2 An electride, a generalized form of cavity-trapped interstitial anionic electrons (IAEs) in a 1234567890():,; positively charged lattice framework, shows exotic properties according to the size and 2+ − geometry of the cavities. Here, we report that the IAEs in layer structured [Gd2C] ·2e electride behave as ferromagnetic elements in two-dimensional interlayer space and possess their own magnetic moments of ~0.52 μB per quasi-atomic IAE, which facilitate the exchange interactions between interlayer gadolinium atoms across IAEs, inducing the ferromagnetism 2+ − in [Gd2C] ·2e electride. The substitution of paramagnetic chlorine atoms for IAEs proves the magnetic nature of quasi-atomic IAEs through a transition from ferromagnetic 2+ − [Gd2C] ·2e to antiferromagnetic Gd2CCl caused by attenuating interatomic exchange interactions, consistent with theoretical calculations. These results confirm that quasi-atomic IAEs act as ferromagnetic elements and trigger ferromagnetic spin alignments within the 2+ antiferromagnetic [Gd2C] lattice framework. These results present a broad opportunity to tailor intriguing ferromagnetism originating from quasi-atomic interstitial electrons in low-dimensional materials. 1 Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea. 2 Center for Integrated Nanostructure Physics, Institute for Basic Science, Suwon 16419, Republic of Korea.
    [Show full text]
  • Room-Temperature Electrides: Discovery, Synthesis, and Applications
    Room-Temperature Electrides: Discovery, Synthesis, and Applications Edmund Tse Literature Seminar October 2, 2012 Electron is generally known as a subatomic particle associated in an orbital of certain energy in atoms and molecules. The energy levels of electrons can also be described using a band structure for bulk materials, such as conductors and semi- conductors. However, on rare occasions, solvated electrons have been observed when alkali metals are dissolved in several amine and ether solvents.1 F-centers, where electrons are trapped in anion vacancies, have been observed for hundreds of years.2 In these cases, the electrons do not belong to a well-defined environment, such as a single atom or shared among a collection of atoms.3 Electrides can be viewed as stoichiometric F-center salts in which electrons fill up all the anionic voids in a crystal structure. Alkalides, which closely resemble electrides, are crystals with alkali metal anions as the counterions. With the exception of Li-, the crystal structures of Na-, K-, Rb- and Cs- have all been solved by James L. Dye and coworkers.4 Although an electron can be viewed as the tiniest anion possible, there is a stark difference between alkalides and electrides. The exact position of each atom in alkalides can be pinpointed, but only the probability density of the electrides can be described. However, alkalides have proven to be useful model systems for studying electrides. The synthesis process of electrides is rather straightforward. By mixing an alkali metal and a complexant in an appropriate solvent, a solution of the complexed cation and the solvated electron can be obtained.
    [Show full text]
  • United States Patent 19 11 Patent Number: 6,103,298 Edels0n Et Al
    USOO6103298A United States Patent 19 11 Patent Number: 6,103,298 Edels0n et al. (45) Date of Patent: *Aug. 15, 2000 54 METHOD FOR MAKING A LOW WORK 58 Field of Search ............................ 427/77, 78, 126.2, FUNCTION ELECTRODE 427/226, 372.2, 384,419.8, 255.6, 255.2, 255.3; 204/290 R 75 Inventors: Jonathan Sidney Edelson, Multnomah County, Oreg.; Isaiah Watas Cox, 56) References Cited London, United Kingdom U.S. PATENT DOCUMENTS 73 Assignee: Borealis Technical Limited, Gibraltar 4,484,989 11/1984 Mansell ................................. 204/59 R 5,128,587 7/1992 Skotheim et al. 313/504 * Notice: This patent issued on a continued pros- 5,675,972 10/1997 Edelson ...................................... 62/3.1 ecution application filed under 37 CFR 5,810,980 9/1998 Edelson ... 204/290 R 1.53(d), and is subject to the twenty year 5,874,039 2/1999 Edelson ............................... 204/290 R E.154(a)(2). sm provisions of 35 U.S.C. Primary Examiner Timothy Meeks This patent is Subject to a terminal dis- 57 ABSTRACT claimer. Methods for making low work function electrodes either made from or coated with an electride material in which the 21 Appl. No.: 08/955,097 electride material has lattice defect Sites are described. 22 Filed: Oct. 22, 1997 Lattice defect Sites are regions of the crystal structure where irregularities and deformations occur. Also provided are Related U.S. Application Data methods for making electrodes which consist of a Substrate coated with a layer of a compound comprised of a cation 63 Continuation-in-part of application No.
    [Show full text]
  • Stable Compound of Helium and Sodium at High Pressure
    Stable Compound of Helium and Sodium at High Pressure Xiao Dong,1, 2, 3 Artem R. Oganov,3-6*, Alexander F. Goncharov,7,8, Elissaios Stavrou,7,9 Sergey Lobanov,7,10 Gabriele Saleh,5 Guang-Rui Qian,3 Qiang Zhu,3, Carlo Gatti,11 Volker L. Deringer12, Richard Dronskowski12, Xiang-Feng Zhou,1, 3* Vitali Prakapenka,13 Zuzana Konôpková,14 Ivan Popov,15 Alexander I. Boldyrev15 and Hui- Tian Wang1,16* 1School of Physics and MOE Key Laboratory of Weak-Light Nonlinear Photonics, Nankai University, Tianjin 300071, China 2Center for High Pressure Science and Technology Advanced Research, Beijing 100193, China 3Department of Geosciences, Stony Brook University, Stony Brook, New York 11794-2100, USA 4Skolkovo Institute of Science and Technology, 3 Nobel St., Moscow 143026, Russia 5Moscow Institute of Physics and Technology, 9 Institutskiy Lane, Dolgoprudny city, Moscow Region, 141700, Russia 6International Centre for Materials Discovery, Northwestern Polytechnical University, Xi’an, 710072, China 7Geophysical Laboratory, CIW, 5251 Broad Branch Road, Washington, D.C. 20015, USA 8 Key Laboratory of Materials Physics and Center for Energy Matter in Extreme Environments, Institute of Solid State Physics, Chinese Academy of Sciences, 350 Shushanghu Road, Hefei, Anhui 230031, China 9Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, P.O. Box 808 L-350, Livermore, California 94550, United States 10Sobolev Institute of Geology and Mineralogy Siberian Branch Russian Academy of Sciences, 3 Pr. Ac. Koptyga, Novosibirsk 630090, Russia. 11Istituto di Scienze e Tecnologie Molecolari del CNR (CNR-ISTM) e Dipartimento di Chimica, Universita’ di Milano, via Golgi 19, 20133 Milan, Italy 12Chair of Solid-State and Quantum Chemistry, RWTH Aachen, D-52056 Aachen, Germany 13Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA 14Photon Science DESY, D-22607 Hamburg, Germany 15Department of Chemistry and Biochemistry, Utah State University, Logan, Utah 84322, USA.
    [Show full text]