scholarly journals Revisiting the Zintl‒Klemm Concept for ALn2Ag3Te5-Type Alkaline-Metal (A) Lanthanide (Ln) Silver Tellurides

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 184 ◽  
Author(s):  
Katharina Eickmeier ◽  
Kai Fries ◽  
Fabian Gladisch ◽  
Richard Dronskowski ◽  
Simon Steinberg
Keyword(s):  
Electronic Structures ◽  
Valence Electron ◽  
Alkaline Metal ◽  
Mixed Metal ◽  
Population Analyses ◽  
Structural Preferences ◽  
Valence Electrons ◽  
First Time ◽  
Electron Transfers ◽  
Metal Bonds

Understanding the bonding nature of solids is decisive, as knowledge of the bonding situation for any given material provides valuable information about its structural preferences and physical properties. Although solid-state tellurides are at the forefront of several fields of research, the electronic structures, particularly their nature of bonding, are typically understood by applying the Zintl‒Klemm concept. However, certain tellurides comprise ionic as well as strong (polar) mixed-metal bonds, in obvious contrast to the full valence-electron transfers expected by Zintl‒Klemm’s reasoning. How are the valence-electrons really distributed in tellurides containing ionic as well as mixed-metal bonds? To answer this question, we carried out bonding and Mulliken as well as Löwdin population analyses for the series of ALn2Ag3Te5-type tellurides (A = alkaline-metal; Ln = lanthanide). In addition to the bonding analyses, we provide a brief description of the crystal structure of this particular type of telluride, using the examples of RbLn2Ag3Te5 (Ln = Ho, Er) and CsLn2Ag3Te5 (Ln = La, Ce), which have been determined for the first time.

scholarly journals Revealing the Nature of Chemical Bonding in an ALn2Ag3Te5-Type Alkaline-Metal (A) Lanthanide (Ln) Silver Telluride

Inorganics ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 70 ◽  
Author(s):  
Kai C. Göbgen ◽  
Kai S. Fries ◽  
Fabian C. Gladisch ◽  
Richard Dronskowski ◽  
Simon Steinberg
Keyword(s):  
Crystal Structure ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Electron Distribution ◽  
Valence Electron ◽  
Alkaline Metal ◽  
Bonding Analysis ◽  
Silver Telluride ◽  
Electron Transfers ◽  
Silver Atoms

Although the electronic structures of several tellurides have been recognized by applying the Zintl-Klemm concept, there are also tellurides whose electronic structures cannot be understood by applications of the aforementioned idea. To probe the appropriateness of the valence-electron transfers as implied by Zintl-Klemm treatments of ALn2Ag3Te5-type tellurides (A = alkaline-metal; Ln = lanthanide), the electronic structure and, furthermore, the bonding situation was prototypically explored for RbPr2Ag3Te5. The crystal structure of that type of telluride is discussed for the examples of RbLn2Ag3Te5 (Ln = Pr, Nd), and it is composed of tunnels which are assembled by the tellurium atoms and enclose the rubidium, lanthanide, and silver atoms, respectively. Even though a Zintl-Klemm treatment of RbPr2Ag3Te5 results in an (electron-precise) valence-electron distribution of (Rb+)(Pr3+)2(Ag+)3(Te2−)5, the bonding analysis based on quantum-chemical means indicates that a full electron transfer as suggested by the Zintl-Klemm approach should be considered with concern.

scholarly journals Probing the Validity of the Zintl−Klemm Concept for Alkaline-Metal Copper Tellurides by Means of Quantum-Chemical Techniques

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2178 ◽  
Author(s):  
Sabrina Smid ◽  
Simon Steinberg
Keyword(s):  
Solid State ◽  
Physical Properties ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Closed Shell ◽  
Alkaline Metal ◽  
Crystal Orbital ◽  
Structural Preferences ◽  
Valence Electrons ◽  
Chemical Techniques

Understanding the nature of bonding in solid-state materials is of great interest for their designs, because the bonding nature influences the structural preferences and chemical as well as physical properties of solids. In the cases of tellurides, the distributions of valence-electrons are typically described by applying the Zintl−Klemm concept. Yet, do these Zintl−Klemm treatments provide adequate pictures that help us understanding the bonding nature in tellurides? To answer this question, we followed up with quantum-chemical examinations on the electronic structures and the bonding nature of three alkaline-metal copper tellurides, i.e., NaCu3Te2, K2Cu2Te5, and K2Cu5Te5. In doing so, we accordingly probed the validity of the Zintl−Klemm concept for these ternary tellurides, based on analyses of the respective projected crystal orbital Hamilton populations (−pCOHP) and Mulliken as well as Löwdin charges. Since all of the inspected tellurides are expected to comprise Cu−Cu interactions, we also paid particular attention to the possible presence of closed-shell interactions.

scholarly journals Revealing the Bonding Nature in an ALnZnTe3-Type Alkaline-Metal (A) Lanthanide (Ln) Zinc Telluride by Means of Experimental and Quantum-Chemical Techniques

Crystals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 916
Author(s):  
Katharina Eickmeier ◽  
Simon Steinberg
Keyword(s):  
Electronic Structures ◽  
Zinc Telluride ◽  
Basic Research ◽  
Alkaline Metal ◽  
X Ray Diffraction ◽  
Unique Type ◽  
Late Transition Metals ◽  
Future Challenges ◽  
Late Transition ◽  
First Time

Tellurides have attracted an enormous interest in the quest for materials addressing future challenges, because many of them are at the cutting edge of basic research and technologies due to their remarkable chemical and physical properties. The key to the tailored design of tellurides and their properties is a thorough understanding of their electronic structures including the bonding nature. While a unique type of bonding has been recently identified for post-transition-metal tellurides, the electronic structures of tellurides containing early and late-transition-metals have been typically understood by applying the Zintl−Klemm concept; yet, does the aforementioned formalism actually help us in understanding the electronic structures and bonding nature in such tellurides? To answer this question, we prototypically examined the electronic structure for an alkaline metal lanthanide zinc telluride, i.e., RbDyZnTe3, by means of first-principles-based techniques. In this context, the crystal structures of RbLnZnTe3 (Ln = Gd, Tb, Dy), which were obtained from high-temperature solid-state syntheses, were also determined for the first time by employing X-ray diffraction techniques.

scholarly journals CAl4Mg0/−: Global Minima with a Planar Tetracoordinate Carbon Atom

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 24
Author(s):  
Nisha Job ◽  
Maya Khatun ◽  
Krishnan Thirumoorthy ◽  
Sasanka Sankhar Reddy CH ◽  
Vijayanand Chandrasekaran ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Valence Electron ◽  
Global Minimum ◽  
Experimental Studies ◽  
Ab Initio Molecular Dynamics ◽  
Global Minima ◽  
Ionic Radii ◽  
Valence Electrons ◽  
Dynamics Simulations ◽  
First Time

Isomers of CAl4Mg and CAl4Mg− have been theoretically characterized for the first time. The most stable isomer for both the neutral and anion contain a planar tetracoordinate carbon (ptC) atom. Unlike the isovalent CAl4Be case, which contains a planar pentacoordinate carbon atom as the global minimum geometry, replacing beryllium with magnesium makes the ptC isomer the global minimum due to increased ionic radii of magnesium. However, it is relatively easier to conduct experimental studies for CAl4Mg0/− as beryllium is toxic. While the neutral molecule containing the ptC atom follows the 18 valence electron rule, the anion breaks the rule with 19 valence electrons. The electron affinity of CAl4Mg is in the range of 1.96–2.05 eV. Both the global minima exhibit π/σ double aromaticity. Ab initio molecular dynamics simulations were carried out for both the global minima at 298 K for 10 ps to confirm their kinetic stability.

Fabrication of YMnO3 Films: New Candidate for Non-Volatile Memory Devices

1996 ◽  
Vol 433 ◽  
Author(s):  
Norifumi Fujimura ◽  
Tadashi Ishida ◽  
Takeshi Yoshimura ◽  
Taichiro Ito
Keyword(s):  
Nonvolatile Memory ◽  
Valence Electron ◽  
Bottom Electrode ◽  
Rf Magnetron Sputtering ◽  
Film Deposition ◽  
Deposition Condition ◽  
Memory Devices ◽  
Non Volatile Memory ◽  
Nonvolatile Memory Devices ◽  
First Time

AbstractWe have proposed ReMnO3 (Re:rare earth) thin films, as a new candidate for nonvolatile memory devices. In this paper, we try to fabricate (0001) oriented YMnO3 films on (111)MgO, (0001)ZnO:Al/(0001) sapphire and (111)Pt/(111)MgO using rf magnetron sputtering. We succeed in obtaining (0001) epitaxial YMnO3 films on (111) MgO and (0001)ZnO:Al/(0001)sapphire substrate, and polycrystalline films on (111)Pt/(1 11)MgO for the first time. Electrical property of the bottom electrode (ZnO:Al) changes with varying the deposition condition of YMnO3 films. However, we find an optimum deposition condition of ZnO:Al film such that it functions as a bottom electrode even after YMnO3 film deposition. The dielectric properties of the epitaxial and polycrystalline YMnO3 films are almost the same. The YMnO3 films show leaky electrical properties. This may be caused by a change in the valence electron of Mn from 3+.

The effect of ionic lattices on the electronic structures of polyatomic ions. I. The triiodide ion

1966 ◽  
Vol 19 (9) ◽  
pp. 1567 ◽  
Author(s):  
RD Brown ◽  
EK Nunn
Keyword(s):  
Electronic Structure ◽  
Molecular Orbital ◽  
Electron Energy ◽  
Electronic Structures ◽  
Valence Electron ◽  
Bond Orders ◽  
Bond Lengths ◽  
Molecular Orbital Study ◽  
Crystalline Environment ◽  
Asymmetric Stretch

A VESCF molecular-orbital study of the electronic structure of the triiodide anion in its crystalline environment in caesium triiodide and in tetraphenylarsonium triiodide reveals the effect of the lattices upon the electronic structures. The calculated total valence-electron energy as a function of the position of the central iodine nucleus provides an understanding of the observed geometries of the anion in the two crystals. The energy plot also implies that the asymmetric stretch of the triiodide is strongly anharmonic in the crystal. A satisfactory correlation exists between observed iodine : iodine bond lengths and computed bond orders.

scholarly journals Structural simplicity and complexity of compressed calcium: electronic origin

2014 ◽  
Vol 70 (3) ◽  
pp. 423-428 ◽  
Author(s):  
Valentina F. Degtyareva
Keyword(s):  
Valence Electron ◽  
Interaction Model ◽  
Outer Core ◽  
Electron Number ◽  
Fermi Sphere ◽  
Simple Cubic ◽  
Valence Electrons ◽  
Cubic Structure ◽  
Structural Simplicity ◽  
Tetragonal Cell

A simple cubic structure with one atom in the unit cell found in compressed calcium is counterintuitive to the traditional view of a tendency towards densely packed structures with an increase in pressure. To understand this unusual transformation it is necessary to assume electron transfer from the outer core band to the valence band, and an increase of valence electron number for calcium from 2 to ∼ 3.5. This assumption is supported by the Fermi sphere–Brillouin zone interaction model that increases under compression. The recently found structure of Ca-VII with a tetragonal cell containing 32 atoms (tI32) is similar to that in the intermetallic compound In5Bi3with 3.75 valence electrons per atom. Structural relations are analyzed in terms of electronic structure resemblance. Correlations of structure and physical properties of Ca are discussed.

scholarly journals Synthesis, Structures and Chemistry of the Metallaboranes of Group 4–9 with M2B5 Core Having a Cross Cluster M–M Bond

Inorganics ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 27 ◽  
Author(s):  
Ranjit Bag ◽  
Suvam Saha ◽  
Rosmita Borthakur ◽  
Bijan Mondal ◽  
Thierry Roisnel ◽  
...  
Keyword(s):  
Metal Carbonyls ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mixed Metal ◽  
Group 4 ◽  
Trigonal Bipyramidal ◽  
Spectroscopic Analyses ◽  
Counting Rules ◽  
Valence Electrons

In an attempt to expand the library of M2B5 bicapped trigonal-bipyramidal clusters with different transition metals, we explored the chemistry of [Cp*WCl4] with metal carbonyls that enabled us to isolate a series of mixed-metal tungstaboranes with an M2{B4M’} {M = W; M’ = Cr(CO)4, Mo(CO)4, W(CO)4} core. The reaction of in situ generated intermediate, obtained from the low temperature reaction of [Cp*WCl4] with an excess of [LiBH4·thf], followed by thermolysis with [M(CO)5·thf] (M = Cr, Mo and W) led to the isolation of the tungstaboranes [(Cp*W)2B4H8M(CO)4], 1–3 (1: M = Cr; 2: M = Mo; 3: M = W). In an attempt to replace one of the BH—vertices in M2B5 with other group metal carbonyls, we performed the reaction with [Fe2(CO)9] that led to the isolation of [(Cp*W)2B4H8Fe(CO)3], 4, where Fe(CO)3 replaces a {BH} core unit instead of the {BH} capped vertex. Further, the reaction of [Cp*MoCl4] and [Cr(CO)5·thf] yielded the mixed-metal molybdaborane cluster [(Cp*Mo)2B4H8Cr(CO)4], 5, thereby completing the series with the missing chromium analogue. With 56 cluster valence electrons (cve), all the compounds obey the cluster electron counting rules. Compounds 1–5 are analogues to the parent [(Cp*M)2B5H9] (M= Mo and W) that seem to have generated by the replacement of one {BH} vertex from [(Cp*W)2B5H9] or [(Cp*Mo)2B5H9] (in case of 5). All of the compounds have been characterized by various spectroscopic analyses and single crystal X-ray diffraction studies.

The effect of the aliphatic carboxylate linkers on the electronic structures, chemical bonding and optical properties of the uranium-based metal–organic frameworks

RSC Advances ◽  
2015 ◽  
Vol 5 (34) ◽  
pp. 26735-26748 ◽  
Author(s):  
Saumitra Saha ◽  
Udo Becker
Keyword(s):  
Optical Properties ◽  
Detailed Analysis ◽  
Computational Methods ◽  
Chemical Bonding ◽  
Electronic Structures ◽  
Computational Study ◽  
Metal Organic Frameworks ◽  
Metal Organic ◽  
First Time

A series of uranyl containing aliphatic dicarboxylate structures is studied using computational methods. Our computational study provides a detailed analysis of these MOFs and explores the effect of linkers on their properties for the first time.

Bandfilling and structural stability of trialuminides: YAl3, ZrAl3, and NbAl3

1991 ◽  
Vol 6 (6) ◽  
pp. 1188-1199 ◽  
Author(s):  
Jian-hua Xu ◽  
A.J. Freeman
Keyword(s):  
Transition Metal ◽  
Structural Stability ◽  
Electronic Structures ◽  
Local Density ◽  
Metal Carbides ◽  
Metal Compounds ◽  
Cohesive Properties ◽  
Valence Electrons ◽  
Stable Forms ◽  
Covalent Interactions

The cohesive properties and electronic structures versus the structural stability of transition-metal trialuminides YAl3, ZrAl3, and NbAl3 in their cubic L12, tetragonal DO22, and naturally stable forms (i.e., the DO19 structure for YAl3 and the DO23 structure for ZrAl3) have been investigated using a total energy local-density approach. The variation of structural stability with transition-metal constituent can be simply understood in terms of the bandfilling of the bonding states in the rigid band sense, with the valence electrons gradually filling the bonding states on going from YAl3, ZrAl3 to NbAl3. This leads to a phase transition from the cubic L12 structure (for YAl3) to the tetragonal DO22 structure (for NbAl3). It is argued that this criterion may also apply to explain the variation of the structural stability of other transition-metal compounds (such as transition-metal carbides, nitrides, silicides, etc.) that are dominated by covalent interactions between the transition-metal d and the metalloid p states.

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