Mn₁₄Al₅₆₊<i>_x</i>Ge_3-<i>_x</i> (<i>x</i> = 0−0.6): A New Intermetallic Phase Containing Unprecedented “Half-Broken” Mackay Icosahedra as Building Units

The new Mn14Al56+xGe3-x (x = 0−0.6) compounds of a new structure type have been synthesized and characterized by physical property measurements and electronic structure calculations. In contrast to their well-known silicon analogues, their unique structure (P3̄) exhibits unprecedented partially destroyed Mackay icosahedra that retain the icosahedral symmetry only in half of the individual polyhedra. The electronic band-structure analysis indicates that the chemical bonding in the structure is still optimized despite the destruction of the Mackay icosahedra and that a further valence electron concentration (VEC) optimization is achieved by the partial occupation of aluminum on a germanium site. The electronic band-structure calculation results were in agreement with the poor metallicity observed for the samples. While the Mn14Al56Ge3 is metallic, the resistivity of Mn14Al56.6Ge2.4 shows a minimum around 20 K and a maximum around 100 K. Both of the samples are Pauli-paramagnetic with an additional small Curie component

Mn₁₄Al₅₆₊<i>_x</i>Ge_3-<i>_x</i> (<i>x</i> = 0−0.6): A New Intermetallic Phase Containing Unprecedented “Half-Broken” Mackay Icosahedra as Building Units

The new Mn14Al56+xGe3-x (x = 0−0.6) compounds of a new structure type have been synthesized and characterized by physical property measurements and electronic structure calculations. In contrast to their well-known silicon analogues, their unique structure (P3̄) exhibits unprecedented partially destroyed Mackay icosahedra that retain the icosahedral symmetry only in half of the individual polyhedra. The electronic band-structure analysis indicates that the chemical bonding in the structure is still optimized despite the destruction of the Mackay icosahedra and that a further valence electron concentration (VEC) optimization is achieved by the partial occupation of aluminum on a germanium site. The electronic band-structure calculation results were in agreement with the poor metallicity observed for the samples. While the Mn14Al56Ge3 is metallic, the resistivity of Mn14Al56.6Ge2.4 shows a minimum around 20 K and a maximum around 100 K. Both of the samples are Pauli-paramagnetic with an additional small Curie component

Mn₁₄Al₅₆₊<i>_x</i>Ge_3-<i>_x</i> (<i>x</i> = 0−0.6): A New Intermetallic Phase Containing Unprecedented “Half-Broken” Mackay Icosahedra as Building Units

The new Mn14Al56+xGe3-x (x = 0−0.6) compounds of a new structure type have been synthesized and characterized by physical property measurements and electronic structure calculations. In contrast to their well-known silicon analogues, their unique structure (P3̄) exhibits unprecedented partially destroyed Mackay icosahedra that retain the icosahedral symmetry only in half of the individual polyhedra. The electronic band-structure analysis indicates that the chemical bonding in the structure is still optimized despite the destruction of the Mackay icosahedra and that a further valence electron concentration (VEC) optimization is achieved by the partial occupation of aluminum on a germanium site. The electronic band-structure calculation results were in agreement with the poor metallicity observed for the samples. While the Mn14Al56Ge3 is metallic, the resistivity of Mn14Al56.6Ge2.4 shows a minimum around 20 K and a maximum around 100 K. Both of the samples are Pauli-paramagnetic with an additional small Curie component

Mn₁₄Al₅₆₊<i>_x</i>Ge_3-<i>_x</i> (<i>x</i> = 0−0.6): A New Intermetallic Phase Containing Unprecedented “Half-Broken” Mackay Icosahedra as Building Units

The new Mn14Al56+xGe3-x (x = 0−0.6) compounds of a new structure type have been synthesized and characterized by physical property measurements and electronic structure calculations. In contrast to their well-known silicon analogues, their unique structure (P3̄) exhibits unprecedented partially destroyed Mackay icosahedra that retain the icosahedral symmetry only in half of the individual polyhedra. The electronic band-structure analysis indicates that the chemical bonding in the structure is still optimized despite the destruction of the Mackay icosahedra and that a further valence electron concentration (VEC) optimization is achieved by the partial occupation of aluminum on a germanium site. The electronic band-structure calculation results were in agreement with the poor metallicity observed for the samples. While the Mn14Al56Ge3 is metallic, the resistivity of Mn14Al56.6Ge2.4 shows a minimum around 20 K and a maximum around 100 K. Both of the samples are Pauli-paramagnetic with an additional small Curie component

New Solid−Gas Metathetical Synthesis of Binary Metal Polysulfides and Sulfides at Intermediate Temperatures: Utilization of Boron Sulfides

A new simple synthetic method for binary metal polysulfides and sulfides was developed by utilizing an in situ formation of boron sulfides and their subsequent reactions with metal-source oxides in a closed container at intermediate temperatures above 350 °C at which the boron sulfides react in a gaseous form. The versatility of the new method is demonstrated with oxides of various transition metals (Ti, V, Mn, Fe, Ni, Nb, Mo, Ru, and W) and rare-earth metals (Y, Ce, Nd, Sm, Eu, Tb, and Er) as starting materials that exhibit different chemical characteristics. Regardless of the oxidation states of metals in the starting materials, the sulfidation reactions occurred quantitatively with stoichiometric mixtures of boron and sulfur, and within 24 h the reactions yielded pure products of TiS2, TiS3, VS4, FeS2, NiS2, NbS3, MoS2, RuS2, WS2, Y2S3, and RS2 (R = Ce, Nd, Sm, Eu, Tb, and Er) which were the thermodynamically stable phases under the reaction conditions. The scope and implications of the new sulfidation method are also discussed

Polymeric Fused-Ring Type Iron Phthalocyanine Nanosheet and Its Derivative Ribbons and Tubes

On the basis of density functional theory calculations, we study the electronic and magnetic properties of an iron phthalocyanine (FePc) nanosheet (FePcNST) and its derivatives, nanoribbons (FePcNRs) and nanotubes (FePcNTs). The GGA+U+SOC calculations reveal that the interesting in-plane magnetic anisotropy comes from unquenched in-plane orbital moments for FePcNST. The calculations indicate that the most stable antiferromagnetic (AFM) ordering for FePcNRs is G-type AFM, which is independent of the ribbon width. In addition, FePcNTs with radii larger than 10 Å are thermodynamically and thermally stable and can be rolled up from the FePcNST with only several millielectronvolts energy cost. Interestingly, the most stable AFM types of FePcNTs highly depend on the number of Fe ions (odd or even) on the circumference. These results may shed useful light on further experimental and theoretical studies on the organometallic nanosheet and its one-dimensional derivatives

PbMnIn₂S₅: Synthesis, Structure, and Properties

The first manganese member in a Pb–M–In–Q system, PbMnIn2S5, has been discovered by a high-temperature solid-state reaction. It adopts a Sr2Tl2O5 structure type in orthorhombic space group Cmcm (No. 63) with a = 3.896(2) Å, b = 12.731(7) Å, c = 15.770(9) Å, and Z = 1. The structure consists of corrugated layers made by (In1/Mn1)­S6 octahedra that are further interconnected by chains of edge-sharing (In2/Mn2)­S6 octahedra into a three-dimensional framework; Pb2+ cations are coordinated in PbS8 bicapped triangular prisms that are face-shared along the a direction. The crystallographically distinguished octahedrally coordinated 8f and 4b sites are disordered by Mn and In atoms. Such a structure allows antiferromagnetic interactions between the high-spin Mn2+ anions. The optical band gap is measured to be about 1.45 eV

Syntheses, Crystal Structures, and Properties of Heterometallic Iodoplumbates: Bicubane, Ribbon, and Chain Configurations

Successful introduction of Cu/Ag cations into the Pb/I system has led to the formation of four unprecedented heterometallic iodoplumbates in which the common connection of PbI6 units has been remarkably altered. Also, interesting long-lived fluorescence properties have been found

Structure-Controlled Solventless Thermolytic Synthesis of Uniform Silver Nanodisks

Monodisperse silver nanodisks are synthesized on the gram scale from a well-characterized layered silver thiolate precursor via thermolysis at 180−225 °C under a N2 atmosphere. XRD, TEM, HRTEM, and AFM analyses indicate that the nanodisks generated at 180 °C over 2 h have an average diameter of about 16.1 nm (σ = ±12%) and a thickness of 2.3 nm (σ = ±14%), and they lie on their (111) faces. The disk shape is considered to be predestined by the crystal structure of the precursor. Important aspects regarding the stability of the precursor, the thermolysis temperature, and the annealing time, as well as a possible conversion mechanism, are discussed

Syntheses, Crystal Structures, and Properties of Heterometallic Iodoplumbates: Bicubane, Ribbon, and Chain Configurations

Successful introduction of Cu/Ag cations into the Pb/I system has led to the formation of four unprecedented heterometallic iodoplumbates in which the common connection of PbI6 units has been remarkably altered. Also, interesting long-lived fluorescence properties have been found