Mn2O3单晶的合成、结构表征及磁性研究

通过助熔剂方法成功地培养了Mn2O3单晶体, 并对其进行了结构分析.     

Synthesis,Crystal Structure,Magnetic Property,and Electronic Structure of Ba2YbInSe5

A new barium ytterbium indium selenide, Ba₂YbInSe₅, was obtained by conventional high temperature solid state reaction. The compound crystallizes in the noncentrosymmetric space group Cmc2₁ of the orthorhombic system. The structure contains infinite one‐dimensional anionic chains ¹_∞[YbInSe₅]^4–, which are built from YbSe₆ octahedra and InSe₄ tetrahedra and separated by Ba²⁺ cation. The magnetic measurement indicates that the compound is paramagnetic. In addition, the calculated bandgap is 0.29 eV.     

Na3B3O3F6: Synthesis,Crystal Structure,and Ionic Conductivity

Crystalline Na₃B₃O₃F₆ was synthesized from H₃BO₃ and NaBF₄ at 623 K, alternatively NaBO₂ can be reacted with NaBF₄ at 673 K. The title compound (C2/c, a = 11.866(7), b = 6.901(4), c = 9.367(6) Å, β = 113.724(9)°) contains the cyclo‐fluorooxotriborate anion B₃O₃F₆^3–, which displays a planar B₃O₃ ring. Within the margins of experimental error, its point group symmetry is D_3h. Layers of fluorinated boroxine rings and sodium atoms are stacked in an alternating manner in parallel to the ab plane. The novel sodium fluorooxoborate is a poor sodium ion conductor with conductivities of 8.7 × 10^–5 and 3.6 × 10^–3 S · cm^–1 at 523 and 623 K, respectively.     

Eu4Bi3: Crystal Structure,Magnetic and Electronic Properties

The Eu? Bi system contains the phases Eu₅Bi₃, Eu₄Bi₃ and Eu₁₁Bi₁₀. The structure types of these phases have been determined by powder X-ray diffraction. Crystals of Eu₄Bi₃ (cubic, space group I4 3d; a = 9.920 Å, Z = 4, T = 130 K, R1/wR2 = 4.86/10.84%) were obtained in low yield by reaction of Eu, Mn, and Bi in the ratio 14:1:11 in a closed niobium tube (heating rate 30°C/h; reaction at 1050°C for 300 h, cooling rate 100°C/h). The crystal structure consists of distorted octahedra made up of six Bi coordinated to a central Eu atom. Eu is also coordinated to a three other Eu atoms and forms a three-dimensional network composed of interconnected rings. The Bi atoms are coordinated to eight Eu atoms. High yields of Eu₄Bi₃ can be prepared by reacting stoichiometric amount of the elements in a sealed tantalum tube at 1100°C for 24 h. Temperature dependent magnetic susceptibility is consistent with antiferromagnetic behavior with an ordering temperature of 18 K. The data could be fit with the Curie-Weiss law and a moment of 7.38 μ_B/Eu is obtained, consistent with all Eu atoms being Eu¹¹. Temperature dependent resistivity indicates that Eu₄Bi₃ is a metal with a room temperature resistance of 1.3 Ωcm.     

A Novel Macrocyclic Nickel(II) and Ferricyanide 1D Zigzag Chain: Synthesis,Crystal Structure,and Magnetic Properties

A novel cyan‐bridged macrocyclic nickel complex [{NiL¹}{Fe(bipy)(CN)₄}]2·5H₂O 1 (L¹ = 3,10‐dimethyl‐1,3,6,8,10,12‐hexaazacyclotetradecane, bipy = 2,2‐bipyridine) was synthesized and structurally characterized. The complex exhibits one‐dimensional zigzag chain structures. Each ferrous(II) ion connects two nickel(II) ions using two trans CN^? groups, and the remaining CN^? groups are terminal. Magnetic measurement shows weak ferromagnetic interaction between the nearest Ni(II) ions through the diamagnetic Fe(II) ion.     

Synthesis,Crystal Structure and Properties of Li2Cu5(PO4)4

Li₂Cu^II₅(PO₄)₄ has been obtained by various reactions starting from copper or Cu₂O. Crystallization was achieved using I₂ as oxidant and mineralizer. The new orthophosphate crystallizes in space group P$\bar{1}$ , Z = 2, with a = 6.0502(3) Å, b = 9.2359(4) Å, c = 11.4317(5) Å, α = 75.584(2)°, β = 80.260(2)°, γ = 74.178(2)°, at 293 K. Its structure has been determined from X‐ray single‐crystal data and refined to R₁ = 0.022{wR₂ = 0.058 for 4633 unique reflections with F_o > 4σ (F_o)}. From magnetic measurements μ_eff = 1.51 μ_B/Cu and θ_P = –37.4 K have been determined. The Vis/NIR spectrum of aqua‐green Li₂Cu₅(PO₄)₄ shows a single broad band centered around $\bar{1}$ = 12000 cm^–1. Magnetic behavior and spectrum are discussed within the angular overlap model.     

Preparation,Crystal Structure,and Magnetic Properties of Rare Earth Ruthenium and Osmium Carbides with La3.67FeC6 Type Structure

The new carbides Gd_3.67RuC₆ and Ln_3.67OsC₆ (Ln = La–Nd, Sm) were prepared by arc‐melting of cold‐pressed pellets of the elemental components. Their hexagonal (P6₃/m) La_3.67FeC₆ type crystal structure was refined from X‐ray powder diffraction data of La_3.67OsC₆ (a = 889.1(1) pm, c = 535.1(1) pm) and Pr_3.67OsC₆ (a = 874.9(2) pm, c = 523.7(1) pm). The occupancy parameters of one La and one Pr site were refined to 0.35(5) and 0.34(5), respectively, in agreement with the highest possible occupancy for steric reasons of 1/3. The C–C distances in the C₂ pairs are 139(6) pm and 137(3) pm, respectively, indicating double bonds. The environment of the osmium atoms is compatible with the 18‐electron rule. The magnetic properties of several carbides were determind with a SQUID magnetometer. The lanthanum compounds La_3.67RuC₆ and La_3.67OsC₆ are Pauli paramagnetic. The magnetic properties of the other compounds are dominated by the magnetic moments of the rare earth atoms. Most order ferrimagnetically with Curie temperatures varying between 5(± 3) and 32(± 6) K for Ce_3.67OsC₆ and Pr_3.67RuC₆, respectively. The cerium atoms in Ce_3.67RuC₆ and Ce_3.67OsC₆ are essentially trivalent, and the samarium compounds show Van Vleck behavior.     

Synthesis,Crystal Structure and Magnetism of the New Oxysulfide Ce3NbO4S3

The orange cerium‐niobium‐oxysulfide Ce₃NbO₄S₃ was synthesized by the solid state reaction of CeO₂, Ce‐metal, Nb₂O₅ and sulfur at 1100 °C. The crystal structure has orthorhombic symmetry (space group Pbam, a = 7.055(1), b = 14.571(3), c = 7.627(2) Å, Z = 4) and contains isolated [Nb₂S₄O₆]¹⁰⁻ ions consisting of two strongly distorted, edge sharing NbO₃SS_2/2 octahedra. Niobium is connected to three oxygen and three sulfur atoms. The cerium atoms are eightfold coordinated by oxygen and sulfur atoms. Certain oxygen and sulfur atoms are not connected to niobium, but exclusively surrounded by cerium. By connecting these cation polyhedra, one recognizes layers of polycations perpendicular to the c‐axis. The magnetic susceptibility shows Curie‐Weiss behavior with an effective magnetic moment μ_eff = 2.63(1) μ_B/Ce in agreement with Ce³⁺. A Weiss‐constant θ_p = –12(1) K indicates weak antiferromagnetic coupling. No magnetic ordering was detected above 2 K.     

Tantalum Clusters in Oxidic Matrices — Synthesis,Crystal Structure and Magnetic Properties of Eu1.83Ta15O32

The mixed‐valent oxotantalate Eu_1.83Ta₁₅O₃₂ was prepared from a compressed mixture of Ta₂O₅ and the metals in a sealed Ta ampoule at 1400 °C. The crystal structure was determined by means of single crystal X‐ray diffraction: space group R3¯, a = 777.2(6) pm and c = 3523.5(3) pm, Z = 3, 984 symmetrically independent reflections, 83 variables, R_F = 0.027 for I > 2σ (I). The structure is isotypic to Ba₂Nb₁₅O₃₂. The salient feature is a [Ta(+8/3)₆O₁₂ⁱO₆^a] cluster consisting of an octahedral Ta₆ core bonded to 12 edge‐bridging inner and six outer oxygen atoms. The clusters are arranged to slabs which are sandwiched by layers of [Ta(+5)₃O₁₃] triple octahedra. Additional Ta(+5) and Eu(+2) atoms provide the cohesion of these structural units. Twelve‐fold coordinated Eu(+2) atoms are situated on a triply degenerate position 33 pm displaced from the threefold axis of symmetry. A depletion of the Eu(+2) site from 6 to 5.5 atoms per unit cell reduces the number of electrons available for Ta‐Ta bonding from 15 to 14.67 electrons per cluster. Between 125 and 320 K Eu_1.83Ta₁₅O₃₂ is semi‐conducting with a band gap of 0.23 eV. The course of the magnetization is consistently described with the Brillouin function in terms of a M_mol/(N_Aμ_B) versus B/T plot in the temperature range 5 K — 320 K and at magnetic flux densities 0.1 T — 5 T. At moderate flux densities (< 1 T) the magnetic moment agrees fairly well with the expected value of 7.94 μ_B for free Eu (2+) ions with 4f⁷ configuration in ⁸S_7/2 ground state. Below 5 K, anisotropic magnetization measurements at flux densities B < 1 T point to an onset of an antiferromagnetic ordering of Eu spins within the layers and an incipient ferromagnetic ordering perpendicular to the layers.     

Synthesis,Crystal Structures,and Magnetic Properties of Two Tetrahedral MnIIMnIII3 Complexes

Two tetranuclear manganese complexes, [NaMn^IIMn₃^III(μ₄‐O^2–)(HL)₃(SCN)₄] ( 1 ) and [NaMn^IIMn₃^III(μ₄‐O^2–)(HL)₃Cl₄][NaMn^IIMn₃^III(μ₄‐O^2–)(HL)₃Cl₃(H₂O)]ClO₄ · 3.5H₂O ( 2 ) were obtained from the reaction of manganese perchlorate with a quadridentate Schiff base ligand, 3‐(2‐hydroxybenzylideneamino)propane‐1, 2‐diol (H₃L) derived from condensation of 2‐hydroxybenzaldehyde with 3‐amino‐1, 2‐propanediol, as well as the coligand KSCN or NaCl under basic conditions. Single‐crystal X‐ray studies reveal that those two complexes all have a mixed‐valent tetrahedral core, which contains an apical Mn^II ion and three basal Mn^III ions situated in the [Mn₃(μ₄‐O^2–)]⁷⁺ equilateral triangle plane. Fitting of the magnetic susceptibility data to the theoretical χ_mT vs. T expression, revealed that the presence of only antiferromagnetic interactions between the central metal atoms in 1 , while both antiferromagnetic and ferromagnetic interactions are present in 2 .     

Synthesis,Crystal Structures,and Properties of Mn(NCS)2 Coordination Compounds with 4-Picoline as Coligand and Crystal Structure of Mn(NCS)2

Reaction of Mn(NCS)₂ with 4-picoline (4-methylpyridine) leads to the formation of [Mn(NCS)₂(4-picoline)₄] · 0.67 · 4-picoline · 0.33 · H₂O ( 1 - Mn ) reported in literature, Mn(NCS)₂(4-picoline)₂(H₂O)₂ ( 2-Mn/H₂O ), and of [Mn(NCS)₂(4-picoline)₂]_n ( 2-Mn/I ). 1-Mn and 2-Mn/H₂O consist of discrete complexes, in which the metal cations are octahedrally coordinated, whereas in 2-Mn/I the metal cations are linked by pairs of μ-1,3-bridging thiocyanate anions into corrugated chains. Measurements using thermogravimetry and differential scanning calorimetry as well as temperature dependent X-ray powder diffraction on 1-Mn and 2-Mn/H₂O reveal that upon heating both compounds transform into [Mn(NCS)₂(4-picoline)]_n ( 3-Mn ) via 2-Mn/I as intermediate. 3-Mn shows a very rare chain topology in which the metal cations are linked by μ-1,3,3 (N,S,S) coordinating anionic ligands which was never observed before with Mn^II. From these investigations there is no hint that a further modification of 2-Mn can be prepared as recently observed for [M(NCS)₂(4-picoline)₂]_n (M = Fe, Cd) and such a form is also not available if the metastable forms of the Fe^II or Cd^II compounds were used as template during thermal decomposition. Magnetic investigations on 2-Mn/H₂O show only paramagnetic behavior, whereas for 2-Mn/I antiferromagnetic ordering is observed. Finally, the crystal structure of Mn(NCS)₂ was determined from XRPD data, which shows that it is strongly related to that of 3-Mn .     

Crystal Structure,Magnetic Properties,and Electronic Structure of Ni(NCNH2)4Cl2 and Co(NCNH2)4Cl2

The crystal structures of Ni(NCNH₂)₄Cl₂ and Co(NCNH₂)₄Cl₂, the first complexes with cyanamide as a neutral ligand, have been determined from single crystal data (Im3m, Z = 6, a = 1259.3(2) pm, R₁ = 0.0245 for Ni(NCNH₂)₄Cl₂ and a = 1266.3(2) pm, R₁ = 0.0241 for Co(NCNH₂)₄Cl₂; both 329 intensities and 23 parameters). Ni²⁺ and Co²⁺ are octahedrally coordinated by four equatorial H₂NCN molecules and two axial chloride ions, and the 20 and 19 electron octahedral complexes are connected by a network of hydrogen bonds. The cyanamide ligands are slightly bent (166°), and the two N–C distances are 112 and 133 pm. Ni(NCNH₂)₄Cl₂/Co(NCNH₂)₄Cl₂ are Curie paramagnets with two/three unpaired electrons.     

Synthesis,Crystal Structure Determination,and Physical Properties of Ag5IO6

The silver iodate(VII), Ag₅IO₆, was obtained by reacting a stoichiometric mixture of Ag₂O and KIO₃, at elevated oxygen pressure, adding a small portion of distilled water. The synthesis was done at 673 K and 270 MPa of oxygen pressure. The crystal structure was solved by direct methods based on single crystal diffraction data ( , Z = 6, a = 5.9366(1), c = 32.1471(6) Å, 323 independent reflections, R₁ = 2.31 %). According to conductivity measurements, Ag₅IO₆ is semiconducting with a specific resistance of 0.08 Ωcm at 300 K. The activation energy was determined as 7.4(1) meV in the temperature range of 220 – 300 K, and 4.3(1) meV in the temperature range of 90 – 180 K. The optical band gap for Ag₅IO₆ is 1.4 eV. Ag₅IO₆ is diamagnetic with a magnetic susceptibility of ?4.4×10^?4 emu/mol.     

Synthesis,Crystal Structure,and Reactivity of Na5[CuO2](OH)2

Na₅[CuO₂](OH)₂ has been obtained as orange single crystals from mixtures of NaOH, Na₂O and Cu₂O in sealed Ag containers. The crystal structure has been refined from X‐ray diffraction data (IPDS data, Pnma, Z = 4, a = 607.4(1) pm, b = 891.2(1) pm, c = 1201.0(2) pm, R₁ = 0.03). The characteristic unit is the bent [CuO₂]^3– complex (∠(O–Cu–O) = 170°). The reactivity of Na₅[CuO₂](OH)₂ has been studied by DSC and in situ X‐ray diffraction techniques. IR spectroscopy has been used for further characterization. The Madelung Part of the Lattice Energy (MAPLE) has been calculated as well.     

CeAgAs2 — a New Derivative of the HfCuSi2 Type of Structure: Synthesis,Crystal Structure and Magnetic Properties

Single crystals of CeAgAs₂ have been obtained by chemical transport reactions starting from a pre‐reacted powder sample. The crystal structure was solved using X‐ray diffraction (space group Pmca, No. 57, a = 5.7586(4) Å, b = 5.7852(4) Å, c = 21.066(3) Å, Z = 8) and refined to a residual of R(F) = 0.029 for 46 refined parameters and 1020 reflections. The structure of CeAgAs₂ represents a new distorted and ordered variant of the HfCuSi₂ type. The characteristic feature of this structure are infinite cis‐trans chains of As atoms with As—As distances of 2.563(1) Å and 2.601(1) Å. CeAgAs₂ is paramagnetic (μ_eff = 2.37 μ_B, θ = —10.5(2) K), with antiferromagnetic ordering at 5.5(2) K and exhibits a metamagnetic transition starting at 4.6 kOe and T = 1.8 K.     

A Novel Ruthenium(III) and Lithium Complex: Synthesis,Crystal Structure,and Magnetic Properties

A novel complex [Li₃{μ‐(H₂O)₆}(H₂O)₆]·[RuCl₆] has been synthesized and was characterized by single‐crystal X‐ray diffraction. The compound crystallizes in rhombohedral space group R3¯c, with the unit cell parameters a = b = 9.948(2)Å, c = 33.376(14)Å, γ = 120°, V = 2860.5(15)ų, Z = 6, D_c = 1.918 Mg m^—3, μ = 1.703 mm^—1, R = 0.0244, wR = 0.0478. The compound consists of a cation, which contains three lithium ions linked by six bridged water molecules, and an anion, which contains a ruthenium(III) ion. The whole complex can be described as a three‐dimensional structure linked by hydrogen bonds between cation and anion. The magnetic properties of the complex have been investigated. The IR, UV‐vis and EPR spectra are studied.     

Synthesis,Crystal Structure,and Properties of the Sodium Molybdate Fluoride Na3MoO4F

The compound Na₃MoO₄F was synthesized by high temperature solution methods. Single‐crystal X‐ray diffraction analysis reveals that Na₃MoO₄F crystallizes in the orthorhombic space group Pnma (No. 62) with lattice constants a = 5.588(2) Å, b = 7.515(3) Å, c = 12.876(5) Å, and Z = 4. The crystal structure consists of isolated MoO₄ groups and [FNa₃]_∞ chains, which are connected by Na–O bonds to form a three‐dimensional framework. A detailed structure comparison between Na₃MoO₄F and NaMoO₃F was carried out. IR spectroscopy and bond valence sum analysis of Na₃MoO₄F indicate that the structure is reasonable. In addition, the electronic structure was investigated by the first‐principles method.     

Crystal Structure and Magnetic Properties of the Novel Oxide Pb2V5O12

The crystal structure of the new oxide Pb₂V₅O₁₂ was determined from X‐ray single crystal and neutron powder diffraction data. The oxide is monoclinic, space group P2/c with a = 8.408(2), b = 5.017(1), c = 11.940(2) Å, β = 98.42(3)°, Z = 2. The crystal structure of Pb₂V₅O₁₂ consists of isolated layers formed by edge and corner sharing VO₅ square pyramids with short vanadyl bonds directed above and below the layers. Six pyramids linked by corner form so‐called “tiling plaquettes”. Neighboring plaquettes are linked by edge sharing. The Pb cations are located in the interstitial positions between layers. The structure of Pb₂V₅O₁₂ is closely related to the MV O_2n+1 homologous series known for Ca, Sr and Cd. Electron diffraction and high resolution electrom microscopy study confirm the crystal structure data and revealed a phase transition induced by irradiation resulting in the formation of a disordered orthorhombic phase (a ≈ 3.75, b ≈ 3.79, c ≈ 5.03 Å) which corresponds to a sublattice of the plaquette‐built structure. The analyses of related structures allowed to suggest a more general formula for this homologous series: M_mV_m+nO_3m+2n. The structures of such compounds may be described by shear planes formed by a shift of the VO₂ units over a 1/2* [110] translation starting from the parent “VO₂” or “MVO₃” structures. Magnetic susceptibility measurements of Pb₂V₅O₁₂ indicate low dimensional behavior and a strong antiferromagnetic exchange within the plaquettes with J of the order of 190 K. Anomalies observed in the susceptibility and the specific heat indicate magnetic order at T_N = 26 K.