Component interactions in {Y, Gd, Tm} - Mo - B ternary systems at 1270 K

X-ray structure analysis has been used to construct isothermal sections at 1270 K for the phase diagrams for the Y - Mo - B and Tm - Mo - B systems. The solubility of MoB₂ in YB₂ is low, while that in TmB₂ is not more than 0.05 molar fraction (lattice constants of the (Tm, Mo)B₂ phase with the AlB₂ structure and limiting composition a=0.3253(2), c=0.3678(4) nm). The existence of some previously known borides is confirmed. and the lattice parameters for some of them have been refined: YMoB₄ (space group Pbam, structure type YCrB₄, a=0.6038(1), b=1.1672(2), c=0.36170(7) nm), YMo₃B₇ (Pnma, own structure type), GdMoB₄ (Pbam, type YCrB₄, a=0.60531(6), b=1.1700(1), c=0.36355(6) nm), Tm₂MoB₆ (Pbam, type Y₂ReB₆), TmMo₂B₇ (Pnma, type YMo₃B₇). New ternary compounds have been identified: Y₃MoB₇ (Cmcm, type Er₃CrB₇, a=0.34775(2), b=1.59793(5), c=0.94757(2) nm), Gd₃MoB₇ (type Er₃CrB₇, a=0.3497(2), b=1.6157(6), c=0.9516(5) nm), and TmMoB₃ (P2₁/m, type ErMoB₃, a=0.6771(2), b=0.3142(1), c=0.5373(1), β=101.48(2)°). The parameters of the metal atoms and their isotropic temperature factors have been refined for Y₃MoB₇ (DRON-3M diffractometer, N_hkl=288, R=0.106). Translated from Poroshkovaya Metallurgiya, Nos, 1–2(411), pp. 56–62, January–February, 2000.     

X-ray studies on phase equilibria in {Tm, Lu} - W - B ternary systems at 1070 K

Isothermal sections at 1070 K have been constructed by x-ray diffraction applied to the phase diagrams in the Tm - W - B and Lu - W - B systems. The solubility of “WB₂” in TmB₂ is low, while that in LuB₂ attains 0.15 molar fraction (lattice parameters of the (Lu, W) B₂ phase with a limiting composition and having the AlB₂ structure a=0.31772(6), c=0.35804(9) nm). The distinct boride reported previously Tm₃WB₇ is confirmed (Er₃CrB₇ structure type). New ternary compounds have been identified and examined by powder method (DRON-3M diffractometer): TmWB₄ (space group Pbam, structure type YCrB₄, a=0.59989(2), b=1.15866(4), c=0.35821(1) nm, N_hkl=157, R=0.0796) and Lu₂WB₆ (Pbam, structure type Y₂ReB₆, a=0.91339(4), b=1.14865(5), c=0.35124(2) nm, N_hkl=408, R=0.0981). Translated from Poroshkovaya Metallurgiya, Nos. 5–6(413), pp. 43–48, May–June, 2000.     

X-ray diffraction investigation of the ternary systems V-Cr-B,Nb-Cr-B,and Mo-Cr-B

Summary The binary compound Cr₅B₃ has a tetragonal structure with the lattice constants a=5.472±0,003, c=10.098±0.006 Å, and c/a=1.845. The phase equilibria in the systems V-Cr-B, Nb-Cr-B, and Mo-Cr-B at 1400°C have been established. In the system V-Cr-B, the continuous solid solutions VB₂-CrB₂, V₃B₄-Cr₃B₄, and VB-CrB have been found; the compound Cr₅B₃ dissolves up to 20 at.% V and the compound V₃B₂ dissolves up to 15 at. %Cr. In the system Nb-Cr-B, the maximum solubility of Cr in the compounds NbB₂ and Nb₃B₂ is 15 and 25 at.%, respectively. The maximum solubilities of a third component in the borides of the system Mo-Cr-B are: 17 at.% Mo in CrB₂, 16 at.% Mo in Cr₃B₄, 40 at.% Mo in CrB, 48 at.% Mo in Cr₅B₃, 6 at.% Mo in CrB₂, and 10 at.% Cr in Mo₂B. In the systems V-Cr-B and Mo-Cr-B, ternary phases with CuAl₂ type structures have been found (the lattice constants are a = 5.188 ±0.004, c=4.318±0.003 Å, and c/a=0.832 for the composition V_0,150–20Cr_1.85–1.80B, and a=5.215–5.245±0.003 and c=4.352–4.383±0.003Å for Mo_0.24–0.39Cr_1.76–1.61 B). The ternary phase (Mo, Cr)₃B₂ has a U₃Si₂ type structure (29–40 at.% Mo, 31–20 at. %Cr, 40 at.% B;'a=5.825–5.774±0.003 and c=3.115–3.082±0.002 Å).Translated from Poroshkovaya Metallurgiya, No. 5, (77), pp. 79–87, May, 1969.     

Reaction of rare-earth metals with boron and aluminum

We have used x-ray phase analysis to establish the phase equilibria at 600°C for the systems Gd-Al-B, Tb-Al-B, and Ho-Al-B (the boron-rich sites have not yet been studied). We determined the crystalline structure of the new borides HoAlB₄ and ErAlB₄ (space group Pbam, YCrB₄ type, a=59283(7), b=1.1553(1), c=0.35306(5) mm for HoAlB₄ and a=0.59955(9), b=1.1487(2), c=0.35284(8) nm for ErAlB₄). We synthesized the compound Tm_1?xAl_1?yB₁₄ with MgAlB₁₄ type structure (space group Imma, a=0.5826(2), b=1.0380(2), c=0.8176(2) nm) by the method of crystallization from an aluminum melt.     

Phase diagrams for the` Lu−Cr−B and Lu−Mo−B systems

X-ray diffraction data have been used in compiling equilibrium phase diagrams for the Lu?Cr?B and Lu?Mo?B systems at 1270 K. The boride LuB₂ dissolves not more than 0.03 molar part of CrB₂ and 0.30 molar part of MoB₂. The existence of compound LuCrB₄ is confirmed (structure of YCrB₄ type) and the same for Lu₂MoB₆ (structure of Y₂ReB₆ type). A homogeneity regions is identified for the boride Lu₂MoB₆, which ranges up to the composition LuMoB₄.     

Isothermal sections of phase-equilibrium diagrams for the systems {terbium,dysprosium}-tungsten-boron at 1270 K

Interaction of components of the systems {Tb, Dy}-W-B have been studied by means of x-ray analysis. Isothermal sections of phase-equilibrium diagrams of the systems at 1270°C have been constructed. The existence of ternary borides with structures of the types YCrB₄ and Er₃CrB₇ has been confirmed. Solid solutions based on binary compounds and other components are not found.     

Synthesis, Characterization, and Reactivity of Amine Bis（phenolato） Cyclopentadienyl Lanthanide Complexes

（C5H5）3Ln（THF）reacted with amine bis（phenol） LH2 [ L = Me2NCH2CH2N {CH2-（2-O-C6H2-But^1-3-Me- 5）}2 ] in a 1：1 molar ratio in THF to generate the amine bis（phenolato） cyclopentadienyl lanthanide complexes LLn（C5H5） （THF）·（THF）,（Ln = La （1）, n =0; Ln = Sm（2）, n = 1） in high yields. Complexes 1 and 2 were fully characterized by elemental analysis, NMR （for 1） and IR spectra, and X-ray structural determination. The crystal data of complex 1 are monoclinic, P21/c space goup, a= 1.1595（1） nm, b = 1.8588（2） nm, c = 1.6647（1） nm, β = 98.490（2）°, V =3.5486（5） nm^3, Z =4, Dc = 1.338 mg· m^3,μ = 1240 mm^-1, F（000）= 1488, R =0.0249, wR = 0.0568. The crystal data of complex 2 are monoclinic, P21/c sp ace goup, a = 0.9692 （1） nm, b = 1.4583 （2） nm, c = 2.8192 （3） nm, = 96.805 （2）°, V = 3.9584 （7） nm^3, Z=4, Dc =1.340 mg · ma, μ = 1.524 mm^-1, F（000）= 1668, R =0.0346, wR =0.0756. The attempts failed to synthesize the amine bis（phenolate） lanthanide alkoxides by the reactions of complexes 1 and 2 with alcohols. The preliminary results revealed that complex 1 can initiate ε-caprolactone polymerization.     

Metal Chemistry of Scandium in Binary Systems Formed with Platinum-Group Metals as the Basis for Construction Multicomponent Systems Based on Those Metals

Major trends are considered in the physicochemical interaction in binary systems formed by scandium with the platinum metals (ruthenium, rhodium, palladium, osmium, iridium, and platinum) from the characteristic features of the phase diagrams and the use of metal-chemical factors governing the formation of intermetallides with various stoichiometry and structure types in those systems (the size, electron-concentration and electronegativity factors). The values for those factors have been established that are favorable to the formation of phases with Sc:Pt´ stoichiometry (Pt´ is a platinum metal), namely: 1:3 (structure type AuCu₃, 1:1 (CsCl type), 11:4 (Zr₁₁Os₄ type), and 44:7 (Mg₄₄Rh₇ type). Published data and the authors' own evidence on the structure of bounding binary systems have been used with evidence on the physicochemical interactions in the Sc Ru Rh system in forecasting the type of phase equilibria occurring in systems of Sc Pt´ Pt´ ´ type (where Pt´, Pt´´ = Ru, Rh, Pd, Ir).     

Equilibrium Phase Diagrams for the Dy ― Al ― B and Er ― Al ― B Systems

X-ray diffraction has been applied to component interactions in order to construct isothermal sections of the phase diagrams for ternary systems Dy Al B at 600°C (region above 50 at.% Al) and 800°C (region below 50 at.% Al) and Er Al B at 800°C. It is confirmed that there are ternary borides: DyAl₃B> _x (structure type BaPb₃, space group R , a = 0.6156(3) nm, and c = 2.109(1) nm), DyAlB₁₄ (type MgAlB₁₄, Imma, a = 0.5819(2) nm, b = 1.0380(3) nm, c = 0.8176(5) nm), ErAlB₄ (type YCrB₄, Pbam, a = 0.59258(7) nm, b = 1.1515(2) nm, c = 0.35340(6) nm), and ErAlB₁₄ (type MgAlB₁₄, Imma, a = 0.5819(1) nm, b = 1.0401(2) nm, c = 0.8189(1) nm). The {Dy, Er} Al B systems lack signs of solid solutions based on binary and ternary compounds.     

The Sc-Mn-B system

XRD has been applied to the component interactions in the Sc-Mn-B system and to construct an isothermal section. The ternary boride Sc_2.28Mn_0.72B₆ has been obtained. The single-crystal method shows that the boride structure belongs to the Y₂ReB₆ structural type: space group Pbam, a = = 0.87810(5) nm, b = 1.10641(6) nm, c = 0.33674(1) nm, 2 θ_max = 24.27 °, N_hkl = 1020, and R_F = = 0.0391. A feature of the new boride is the random distribution of the Sc and Mn atoms in positions with the smaller coordination number in the compound structure. Component interaction has been examined in the systems Sc-M-B, where M is a transition metal.     

Phase Equilibria in the Lu ― V ― B System and the Structure of the New Boride Lu1.34V1.66B6

X-ray diffraction data have been used to construct the 1070 K isothermal section of the Lu V B phase diagram. The solubility of VB₂ in LuB₂ attains 5 at.% (lattice parameters of the (Lu, V)B₂ phase of the limiting composition with the AlB₂ structure are a = 0.3238(1), c = 0.3689(1) nm). A new ternary boride has been discovered, Lu_1.34V_1.66B₆, which belongs to the Y₂ReB₆ structure type (space group Pbam, a = 0.8947(8), b = 1.1273(7), c = 0.3381(2) nm, F _hkl > 4(F), 2thetav;_max = 72.76°, N _hkl = 379, R _F = 0.0617, R _w = 0.0653) and is characterized by a statistical distribution of the Lu and V atoms in one of the structure positions.     

X-ray diffraction study of the system tungsten-rhenium-carbon

Conclusions The system W-Re-C was studied by the method of x-ray structural analysis. Phase equilibria were established for as-cast alloys and alloys quenched from 2000, 1500, 1000, and 800°C. Rhenium and -W₂C form continuous series of solid solutions. Forthe composition W₃Re₂C, there exists a ternary compound with a cubic structure which is related to the -Mn structure (space group P4₁ 3-O⁷, a=6.859±0.002 A). At temperatures above 2500°C, there exists the ternary carbide (W, Re)C, which has a cubic face-centered NaCl type structure (space group Fm3m-O _h ⁵ , a==4.063± 0.001 A). Preliminary data were obtained on the existence of a rhombic low-temperature W₂C modification.     

Re-determination of the crystal structure of Ca2Y8Si6O26 and study on the luminescent properties of Ca2Y8Si6O26:Tb3+

The crystal structure of silicate oxyapatite Ca₂Y₈Si₆O₂₆ was indexed as hexagonal, space group P6₃/m, α=0.93515 nm, c=0.67872 nm, α=β=90°, γ=120°, V=0.5138692 nm³. Three strong peaks located at 32.079°, 32.595°, and 50.104° with d=2.7903, 2.74649, 1.8194 was in accordance with (211), (112), and (213) planes. The optimum concentration of Tb³⁺ in Ca₂Y₈Si₆O₂₆ to yield highest photoluminescence intensity was 10 mol.% of Y³⁺. The corresponding excitation spectrum consisted of an intense broad band from 220 to 260 nm. The photoluminescence measurements showed that the green emission originated from ⁵D₄?⁷F₅ was predominant in the measured range with strong doublet lines at 543 and 549 nm.     

Features of electrodeposition of “nickel-chromium diboride nanopowder” composite coatings

Conditions for obtaining a nickel-based composite electrochemical coating (CEC) with the use of the CrB₂ nanopowder as a strengthening phase in a standard nickel plating electrolyte are investigated. It is established that the nickel matrix is maximally saturated with the use of chromium nanoboride upon its concentration in the electrolyte of 5–10 kg/m³, which is lower by a factor of 8–12 than when adding CrB₂ micropowders. The microhardness of the CEC with the Ni-CrB_2(nano) composition with the content of the strengthening phase of 0.59–0.65% is higher than for the Ni-CrB_2(micro) coatings containing 2.47–2.86% boride by a factor of 1.16–1.19 and for the nickel host by a factor of 1.64–1.86. The optimal conditions of the CEC deposition are a cathode current density of 1.0 kA/m², a nanoboride concentration in the electrolyte of 5–10 kg/m³, pH = 5.0–5.5, and a temperature of 323 K.     

New compounds with a Y2ReB6 type structure

The Ln’Mo’MB ternary systems (where Ln is Tm, Yb, Lu) are studied by means if X-ray analysis. New compounds of the Y2ReB6 structure type (space group Pbam) were found: Tm₂MoB₆ (a=0.9210(2), b=1.1409(1), c=0.35983(6) nm), Yb₂MoB₆ (a=0.9068(3), b=1.1394(3), c=0.3588(1) nm), Lu₂MoB₆ (a=0.9031(4), b=1.1364(3), c=0.35526(9) nm); the atomic factors of the last structure are refined up to R=0.068. Lattice parameters for the known boride Er₂MoB₆ are refined: a=0.925492), b=1.1449(3), c=0.36065(6) nm. The smoothly decreasing lattice parameters and unit cell volumes in the series Ln₂MoB₆ (Ln is Er, Tm, Yb, Lu) point to the trivalent state of the rare earth atoms (REM).     

Synthesis, crystal structure and fluorescence of a new europium complex with 2-bromobenzoate and 2,2′-bipyridine

A new complex of {[Eu2(2-BrBA)6(2,2'-bpy)2]2.CH3CH2OH·H2O} (2-BrBA=2-bromobenzoate; 2,2'-bpy=2,2'-bipyridine) was prepared by solvent method and characterized with X-ray single-crystal diffraction, IR spectroscopy, UV spectrscopy, and fluorescence spectroscopy. The complex crystallized in triclinic crystal system, PT space group, with a=1.17196(4) nm, b=-2.36142(9) nm, c=2.59151(9) nm, a=113.266(2)°, β=101.100(2)°, and γ=94.400(2)°. Two independent dinuclear molecules were contained in the asymmetric unit. The two molecules were similar to each other. Each Eu(Ⅲ) ion was nine-coordinated with seven oxygen atoms from five 2-BrBA ligands and two ni-trogen atoms from 2,2'-bpy molecule. The carboxylate groups acted as bidentate-chelating, bidentate-bridging and chelating-bridging coor-dination modes. The complex adopted a distorted monocapped square-antiprism coordination geometry. Five peaks at 579, 591, 613, 652,and 697 nm appeared in the fluorescence spectrum, corresponding to 5D0→7F0, 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transition emis-sions of the Eu(Ⅲ) ion, respectively.     

Standard gibbs energies of formation of the carbides of manganese by emf measurements

The standard Gibbs energies of formation of Mn₇C₃, Mn₅C₂, Mn₁₅C₄, and Mn₂₃C₆ have been obtained from emf measurements using galvanic cells of the type (-)Mn, MnF₂, CaF₂//CaF₂//CaF₂, MnF₂, ‘Mn-C’(+) The measurements have been carried out in the temperature range 909 to 1247 K. In the case of measurements with Mn-C alloy containing 12.9 wt pct C (Mn₇C₃-C two-phase region at room temperature), the slope change in the emf-temperature curve at 1181 K suggests the formation of a hitherto unidentified phase above this temperature.     

The crystal structures of Hf3N2 and Hf4N3

The crystal structures of ε-Hf₃N₂ and ζ-Hf₄N₃ were determined from X-ray powder photographs. The structure of both phases is trigonal, space group D ₅ ^3d -R?3m, with unit cells ofa _R = 7.972Å, α= 23 deg 12 min (hexagonal axes:a = 3.206Å,c = 23.26Å) for ε-H₃H₂, and a_R= 10.54Å, α = 17 deg 32 min (hexagonal axes:a = 3.214Å,c = 31.12Å) for ζ-Hf₄N₃. The nine close packed metal layers in ε-Hf₃N₂ are stacked according to (hhc)₃, or ABABCBCAC. The structure of ζ-Hf₄sN₃, isomorphous with ζ-V₄C₃,¹ consists of twelve close-packed metal layers in a stacking sequence (hhcc)₃. The nitrogen atoms occupy octahedral interstices in the metal lattice. The experimentally observed compositions, Hf₃N₁.₆₉ and Hf₄N₂.₅₆, shows both phases to be substantially deficient in nitrogen. ε-Hf₃N₂ is unstable above 2000°C, and ζ-Hf₄N₃ above 2300°C.     

Reaction of Vanadium and Molybdenum with Phosphorus

We have used x-ray diffraction to study the reaction of elements in the system V – Mo – P in the region 0-0.67 mole fraction P and we have plotted the isothermal cross section of the phase diagram at 1070 K. We have confirmed the presence of solid solutions based on V₃P, Mo₃P, VP, MoP, and we have also found solid solutions based on V₂P (up to the composition ～V_1.8Mo_0.2P), V₁₂P₇ (up to the composition V_11.0Mo_1.0P₇), MoP₂ (up to the composition ～Mo_0.8V_0.2P₂). We have observed a new ternary compound of variable composition V_9.5-3.5Mo_2.5-8.5P_6.5. We used the powder method to study crystal structure of this compound (space group P¯6, structural type (Ti, Mo)₁₂P₇, a = 1.6236(2)-1.6773(3) nm, c = 0.3266(1)-0.3327(1) nm, R _I = 0.079 and R _P = 0.136 for the composition V_6.0Mo_6.0P_6.5) and atomic coordinates.     

Synthesis and Characterization of the First Dinuclear Europium （Ⅱ） Complex Supported by Carbon-Bridged Biphenolate Ligand

Amongpossiblealternativestothetraditionalan cillaryligandbis(cyclopentadienyl)setinrareearth metalchemistry,alkoxides(aryloxides)havereceived muchattentionandbecomeincreasinglypopularsince theyareeasilyavailable,tunableandevenpotentially recyclableancillarysetsformediatingthereactivityof theseelectropositivecations[1,2].Thechelatebiphenol andbinaphtholhavebeenfoundtobeabletoactasa dianionicligandintherareearthchemistry,whichhas theadvantagesofavoidingligandredistributionreac tions,andallowingth…