Ternäre Bromide und Iodide zweiwertiger Lanthanide und ihre Erdalkali-Analoga vom Typ AMX3 und AM2X5

Ternary Bromides and Iodides of Divalent Lanthanides and Their Alkaline-Earth Analoga of the Type AMX₃ and AM₂X₅ Metallothermic reduction of the tribromides and -iodides MX₃ (M = Sm, Dy, Tm, Yb) with alkali metals as well as with indium and thallium (A = Cs, Rb, K, In, Tl) results in most cases in ternary compounds with the composition AMX₃ and AM₂X₅, respectively. Analogous compounds with M = Ba, Sr, Ca were synthesized from the binary components. The AMX₃ compounds crystallize with the following types of structure: the perovskite-type and its distorted variants, the NaNbO₃-II- and the GdFeO₃-type, the NH₄CdCl₃- and the stuffed PuBr₃-type. These structure types differ by a gain of condensation of the [MX₆] octahedra (three-dimensional connection via corners within the variants of the perovskite-type, double chains of edge- and face-connected octahedra within the NH₄CdCl₃-type, and layers of corner- and edge-connected octahedra within the stuffed PuBr₃-type of structure). This comes along with a reduction of the coordination number of A⁺ from 12 (“ideal” perovskite) to 8 + 2 (GdFeO₃-type), 9 (NH₄CdCl₃-type), and 8 (stuffed PuBr₃-type). Thus, the A/[MX₆] size ratio determines which AMX₃ type of structure is adopted. If the M²⁺ ion is large enough, ternary compounds with the composition AM₂X₅ occur either in addition to the AMX₃ compounds or exclusively. They crystallize with the TlPb₂Cl₅ type of structure (C.N.(M²⁺) = 7 and 8). All of the AMX₃ and AM₂X₅ compounds are summarized in a structure field diagram.     

Structural correlations of the lanthanide halides and related compounds. Derivatives of the anti-nickel-arsenide structure

An examination of structural data for lanthanide halides and related compounds has shown that a substantial number of different structure types are conveniently described as layered structures derived from anti-NiAs by removal or shear of cation layers and distortion of the residual layers. The structural correlations of various MX, MX_1.5, MX₂, MXY, MX₃, and MX₂Y compositions (M = cation, X and Y = anions) are described by the presentation of a subgroup-supergroup diagram relating their space groups and by comparison of their structural projections. A close relationship between the CsCl- and NiAs-type structures is observed. The occurrence of displacive and order-disorder phase transitions, the formation ternary derivatives by ion accommodation processes and the possible formation of intermediate halides, M₂X_2n+1, by coherent intergrowth of MX₂ and MX₃ structures are discussed. The effects of radius ratio and cation coordination number on the stabilities of halide structures and on the formation of complex MX₂ layers derived from hexagonal-closest-packed metal arrays are examined.     

Living cationic polymerization of vinyl ethers and styrene derivatives: Design of initiating systems based on added salts with halogen anions

This paper overviews three living cationic polymerization systems (for styrene, p-methoxystyrene, and isobutyl vinyl ether) that are, in common, featured by: (i) specifically in nonpolar solvents, the use of the hydrogen halide/metal halide initiating systems (HX/MX_n; X: I, Br, Cl; MX_n: ZnX₂, SnCl₄), which generate a living growing carbocation stabilized by a nucleophilic counteranion (X⁻…MX_n); (ii) specifically in polar solvents, the use of externally added ammonium salts (nBu₄N⁺Y⁻; Y⁻: I⁻, Br⁻, Cl⁻), which permit the generation of living species from HX/MX_n by providing nucleophilic halogen anions Y⁻, either the same as or different from the halogen X⁻ in HX.     

Syntheses, structures, and magnetic and optical properties of the compounds [Hg3Te2][UCl6] and [Hg4As2][UCl6]

Two new quaternary salts, [Hg₃Te₂][UCl₆] and [Hg₄As₂][UCl₆], have been synthesized and their structures determined by single-crystal X-ray diffraction analysis. [Hg₃Te₂][UCl₆] is the product of a reaction involving UCl₄, HgCl₂, and HgTe at 873 K. The compound crystallizes in space group P2₁/c of the monoclinic system. [Hg₄As₂][UCl₆] results from the reaction of U, Hg₂Cl₂, and As at 788 K. It crystallizes in space group Pbca of the orthorhombic system. [Hg₃Te₂][UCl₆] has a two-dimensional framework of layers, whereas [Hg₄As₂][UCl₆] has a three-dimensional framework of layers interconnected by Hg atoms linearly bonded to As atoms. Both framework structures contain discrete [UCl₆]²⁻ anions between the layers. [Hg₃Te₂][UCl₆] exhibits temperature-independent paramagnetism. The optical absorption spectra of these compounds display f-f transitions.     

Die Reaktion von UV- und UVI-Verbindungen mit SOCl2

Reaction of U^V and U^VI Compounds with SOCl₂ UO₃, UO₂Cl₂, UCl₆, and UCl₅ reacted with OSCl₂ yield always UCl₅ · SCl₂, [SCl₃]⁺ [UCl₆]^? or a mixture of these compounds, but not an adduct UCl₅ · OSCl₂. An X-ray study was carried out with single crystals of [SCl₃]⁺[UCl₆]^?. It crystallizes in the orthorhombic space group P2₁2₁2₁ with the lattice constants a = 1066.8, b = 1071.2, c = 1133.3 pm and with Z = 4, containing isolated pyramidal SCl₃⁺ (r_SCl = 196.2 ± 1.1 pm ?SCl₂ = 102.34 ± 1.13°) and octahedral UCl₆^? ions (r_UCl = 251.1 ± 2.6 pm).     

The stereochemistry of Tutton's salts X2[M(H2O)6](YO4)2

Neutron structure determinations have been made of Tutton's salts, X₂[M(H₂O)₆] (YO₄)₂, where Y = Se, X = K⁺, M = Cu²⁺; Y = S, X = K⁺, M = Ni²⁺, Cu²⁺, Zn²⁺; X = Rb⁺, Cs⁺, M = Cu²⁺. This work has shown that there are extensive hydrogen networks with almost linear hydrogen bonds from [M(H₂O)₆]²⁺ to (YO₄)^2?. The (H … O) distance increases in the Cu²⁺ series for X = K⁺ to Cs⁺ but there is no difference for the potassium copper salts when Y = Se or S. Three different distorted [M(H₂O)₆]²⁺ octahedra were found in the series (orthorhombic, tetragonal with two long and four short, or four long and two short bonds). The interatomic distances from X⁺ to the neighboring O in a distorted XO₈⁺ dodecahedron increases with increased cation size, implying that the X⁺ polyhedron is maintaining its shape.     

Structural Study of Li1+x−yNb1−x−3yTix+4yO3 Solid Solutions

The structures of Li_1+x−yNb_1−x−3yTi_x+4yO₃ solid solutions within the so-called M-phase field in the Li₂O-Nb₂O₅-TiO₂ system were investigated using high-resolution transmission electron, microscope (HRTEM) and single-crystal X-ray diffraction. The results demonstrated that the phase field is not a solid solution but rather a homologous series of commensurate intergrowth structures with LiNbO₃-type (LN) slabs separated by single [Ti₂O₃]²⁺ corundum-type layers. The thickness of the LN slab decreases with increasing Ti-content from ∼55 to 3 atomic layers in the metastable H-Li₂Ti₃O₇ end-member. The LN slabs accommodate a wide range of Ti⁴⁺/Nb⁵⁺ substitution, and for a given homolog the distribution of Ti and Nb is not uniform across the slab. A single-crystal X-ray diffraction study of a structure composed of nine-layer LN slabs revealed preferential segregation of Ti to the slab surfaces which apparently provides partial compensation for the charge on the adjacent [Ti₂O₃]²⁺ corundum layers. The extra cations in phases with x>0 are accommodated through the formation of Li-rich Li₂MO₃-type layers in the middle of the LN slabs. The fraction of layers with extra cations increases with increasing Ti-content in the structure.     

Expanded polycationic mercury-chalcogen networks in the layered compounds Hg3E2[MX6] (E=S, Se; M=Zr, Hf; X=Cl, Br)

The reactions of HgE (E=S, Se) with HgX₂ and MX₄ (M=Zr, Hf; X=Cl, Br) in evacuated glass ampoules lead to a series of isotypic compounds of the general formula Hg₃E₂[MX₆] in the form of colorless (X=Cl) and light-yellow (X=Br) air-sensitive crystals. The crystal structures of Hg₃S₂[ZrCl₆] (I), Hg₃S₂[HfCl₆] (II), Hg₃Se₂[ZrCl₆] (III), Hg₃Se₂[HfCl₆] (IV), Hg₃S₂[ZrBr₆] (V), and Hg₃Se₂[ZrBr₆] (VI) were refined based on single-crystal data. All compounds crystallize in the monoclinic space group P2₁/a with the lattice parameters a=662.18(2) pm, b=734.97(3) pm, c=1290.83(5) pm, β=91.755(2)° for (I) and and a=701.97(3) pm, b=756.79(3) pm, c=1350.99(6) pm, β=92.164(3)° for (VI). The structures are built of (Hg₃E₂)²⁺ layers stacked perpendicular to the c-axis. The polycationic layers consist of two-dimensionally linked 12-membered Hg₆E₆ rings in the chair conformation with linear coordinated Hg and trigonal pyramidal coordinated chalcogen atoms. Almost regular octahedral [MX₆]²⁻ ions are embedded between the layers. This arrangement is closely related to the structure of Hg₃S₂[SiF₆], which represents a higher symmetric congener. The structure relation is discussed using the supergroup-subgroup relation between space groups.     

Structure and stability of oligomeric anions [M n X3 n + 1]? (M = Al, Ga, In; X = F, Cl, Br, I; n = 2–4): A quantum-chemical study

The structural and thermodynamic properties of oligomeric anions [M _n X_{3n+ 1}]⁻ (M = Al, Ga, In; X = F, Cl, Br, I; n = 2, 3, 4) have been obtained by the density functional theory B3LYP method with the LAN2DZ(d) and LAN2DZ(d)+ basis sets. A wide diversity of structural isomers was found for trimeric fluoride anions M₃F₁₀⁻. Among the trimers, except In₃F₁₀⁻, the most stable is a linear isomer composed of two MX₃ molecules coordinated to the MX₄⁻ anion. The formation of tetrameric anions M₄X₁₃⁻ was demonstrated to be thermodynamically allowed at low temperatures at MX₃: X⁻ > 4: 1. The existence of higher oligomers is less probable. The affinity of oligomer halides (MX₃) _n for halide ions increases with an increase in n. The propensity to form oligomeric anions decreases in the series F > Cl ≥ Br > I. The fluoride systems show a tendency to form structures with CN = 5 and 6, these structures for In being the most stable. Original Russian Text ? A.Yu. Timoshkin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 87–100.     

Die Chloride Na3xM2–xCl6 (M = La?Sm) und NaM2Cl6 (M = Nd,Sm): Derivate des UCl3-Typs. Synthese,Kristallstruktur und Röntgenabsorptionsspektroskopie (XANES)

The Chlorides Na_3xM_2–xCl₆ (M = La? Sm) and NaM₂Cl₆ (M = Nd, Sm): Derivatives of the UCl₃-Type of Structure. Synthesis, Crystal Structure and X-Ray Absorption Spectroscopy (XANES) Single crystals of the derivatives of the UCl₃-type structure Na_3xM_2–xCl₆ (M = La/x = 0.364(4); Ce/0.349(5); Pr/0.318(8); Nd/0.305(5); Sm/0.246(4)) and NaSm₂Cl₆ were grown by different methods generally under reducing conditions. They are addition [Na(Sm₂)Cl₆] and addition/substitution variants [Na_2x(Na_xM_2–x)Cl₆] of the UCl₃ structure type [□(U₂)Cl₆]. X-Ray Absorption Spectroscopy (XANES) at the L_III edge characterizes NaSm₂Cl₆ and NaNd₂Cl₆ as mixed-valence compounds with valences of +2 and +3 in statistical distribution (approximately 1:1) for Sm and Nd, respectively.     

The interaction of silver ions with the isothiocyanatopenta-amminechromium(III) cation

The reaction of the isothiocyanatochromium(III) ion with silver ions produces adducts of the type [Cr(NH₃)₅NCSAg_n]X_n+2. For X = ClO₄, n = 1 and for NO₃, n = 2.     

Mass spectra of complexes of 8-quinolinol with trivalent metals (AL,Ga, In,Sc, Cr and Fe)

The main fragmentation of the compounds MX_3-nox_n (oxH=8-quinolinol. n = 3; M=AL, Ga, In, Sc, Cr or Fe. n = 2; M=In or Fe; X=Cl or Br. InIox₂. n = 1; M=AL, In or Fe; X= Cl or Br) involves loss of X and intact ox_. radicals. The comparative abundances of the fragments are primarily related to the common oxidation states of the metals. For example, all the Mox₃ compounds show the ions [Mox₃]⁺ and [Mox₂]⁺. The ions [Mox]⁺ and [M]⁺ are present when M=Ga, In, Cr or Fe but for the elements with only one oxidation state (Al or Sc) [M]⁺ is absent and [Mox]⁺ has only very low abundance. When M= Cr or Fe metal-containing ions arising from loss of species such as CO, H₂O, HX, C₂H₂, H and OH by fragmentation of the ox ligand are also present; this behaviour is rationalised in terms of the ability of these metals to undergo a unit change in oxidation state. When n=1 the ions [MXox₂]⁺ and [Mox₂]⁺ and when n= 2 the ions [MX₂ox]⁺ and [Mox₃]⁺ are present; these ions arise by ionization and fragmentation of species formed by redistribution reactions in the mass spectrometer.     

Niobium-chloride octahedral clusters as building units for larger frameworks

A systematic theoretic study on clusters containing edge-bridged octahedral metal units [Nb₆Cl₁₂] ⁿ (n?=?2, 3, or 4) and a large variety of ligands has been performed. The benchmark results on the [Nb₆Cl ₁₂ ⁱ ] ⁿ⁺ and [Nb₆Cl ₁₂ ⁱ Cl ₆ ^a ] ⁿ (n?=?2, 3 or 4) cluster units demonstrated the reliability of GGA PBE functional in combination with ZORA TZP basis set for the Nb-containing coordination compounds. The geometrical, electronic, and vibrational properties of large variety of substituted Nb₆Cl ₁₂ ⁱ Y ₆ ^a clusters have been provided. One- and two-dimensional structures with a [Nb₆Cl ₁₂ ⁱ (Bipyr) _x Cl _6?x ^a ] (x?=?2 and 4) building blocks have been proposed as good and stable candidates for new coordination polydimensional materials.     

The extraction of thulium(III), dysprosium(III) and samarium(III) by dioctylarsinic acid in chloroform

Dioctylarsinic acid, HDOAA, in chloroform (0.1 M) extracts thulium(III), dysprosium(III) and samarium(III) from their aqueous solutions in the pH ranges 1–6.5, 2–7 and 4–8, respectively, with extraction coefficients of approximately 0.1 for the lowest and 10 for the highest pH. The extractability increased with increasing ionic strength for each ion and decreased in the order ClO₄^- > NO₃^- > Cl^- > SO₄^2- > acetate for solutions of the same molarity. pH-Dependence curves had slopes ranging from 1.05 to 1.87. The reagent-dependence studies gave curves with slopes between 3.60 and 5.30. The general formula [MX_n(DOAA)_m(HDOAA)_p(H₂O)_q] (X = Cl^-. NO₃^-, SO₄^2-/2, ClO₄^-, acetate, OH^-; n+m=3, m+p=4 or 5, q?0)is suggested for the extracted species.     

Mössbauer spectroscopic studies of molecule-based magnets: NBu4[Fe(II) x Mn(II)1-x Cr(III)(ox)3] and NBu4[Fe(II) x Ni(II)1-x Fe(III)(ox)3]

The internal magnetic field (H _n ) at⁵⁷Fe nucleus was investigated for the mixed crystals, NBu₄[Fe(II) _x Mn(II)_1-x Cr(III) (ox)₃] (x=0.03?1) and NBu₄[Fe(II) _x Ni(II)_1-x Fe(III)(ox)₃]) (x=0?1) using Mössbauer spectroscopy, where NBu₄/⁺=tetra(n-butyl)ammonium ion and ox^2?=oxalate ion. With the decrease ofx, the direction ofH _n at Fe(II) in NBu₄[Fe(II) _x Mn(II)_1-x Cr(III)(ox)₃] changed gradually from parallel to perpendicular, to the honeycomb layers consisting of an alternate array of the bivalent and tervalent ions through ox^2? ligands. A variation of ca. 50° in direction was observed for theH _n at Fe(III) in NBu₄[Fe(II) _x Ni(II)_1-x Fe(III)(ox)₃].     

Neue Derivate des UCl3-Typs: Die Chloride und Bromide A(SrSm)Cl6, A(SrEu)Cl6 und A(BaLa)X6 (A = Na,Ag; X = Cl,Br)

New Derivatives of the UCl₃ Type of Structure. The Chlorides and Bromides A(SrSm)Cl₆, A(SrEu)Cl₆, and A(BaLa)X₆ (A = Na, Ag; X = Cl, Br) The UCl₃ type of structure may be understood as a distorted hexagonal closest packing of spheres of the general composition MX₃ (space group P6₃/m, Z = 2). The empty channels parallel [001] may be filled partially with monovalent cations (A⁺). Addition/substitution derivatives are obtained according to A^I(B^IIM^III)X₆. Chlorides of the idealized composition A(SrSm)Cl₆, A(SrEu)Cl₆, and A(BaLa)Cl₆ as well as bromides A(BaLa)Br₆ (A = Na, Ag) were synthesized. Details of the crystal structures of Na(SrSm)Cl₆, Ag(SrEu)Cl₆, and Na(BaLa)Br₆ were determined. Ionic conductivity measurements were carried out for Na(SrSm)Cl₆, Ag(SrSm)Cl₆ and Na(BaLa)Br₆ by impedance spectroscopy.     

M/Xn (MAl,Mg; XBr,I) batteries based on anion transport mechanism

A new type of electrochemical storage energy batteries of M/X_n (MAl, Mg; XBr, I, n = 3, 2) were found. They can operate with nonaqueous electrolyte or solid electrolyte showing high voltage and moderate rate performances. The discharging mechanism is related to the formation and growth of the electrolyte phase MX_n on the surface of M electrode. The MX_n phase is X⁻ conductor and X⁻ anions play the transport role in electrode and electrolyte in these systems. Our finding shows that anion-conducting electrochemical batteries can be also promising for energy storage compared to cation-conducting systems in current batteries.     

Plasma desorption mass spectrometry of transition metal complexes of thio- and selenosemicarbazones of 2-acetylpyridines

Summary Californium-252 plasma desorption mass spectra were recorded for complexes of the anions of various thio-and seleno-semicarbazones of 3-acetylpyridines(1–4) with the transition metal ions iron(III) and cobalt(II). Positive ion spectra gave clear evidence of the cation present and fragmentation with loss of ligands or parts of ligands was straightforward. Negative ion spectra likewise provided evidence of the intact anion except with tetracoordinate metal halide systems [MX₄]^– which lost one or more halide atoms. Evidence of fragmentation of the ligand and recombination of the fragments with the metal ion was also observed in the negative ion mode. Spectra were used to revise the structure of a complex previously reported as [FeLCl₂]⁽¹⁾ to [FeL₂]⁺[FeCl₄]^–.     

The solid state reaction between hexaamminechromium(III) complexes and L-α-alanine

The solid reaction between [Cr(NH₃)₆]X₃(X^? = Cl, I, SCN and NO₃) and L-α-alanine was studied under continuous rise in temperature and isothermal heating. Under continuous rise in temperature, the main products were [Cr(NCS)₃-(NH₃)₃] (X^? = NCS) and [Cr(L-ala)₃] (X^? = NO₃), when [Cr(NH₃)₆]Cl₃ and [Cr(NH₃)₆]I₃ as starting complexes were used; in both cases only the decomposition proceeds. Under isothermal heating at 150°C the main products were [CrCl(NH₃)₅]-Cl₂ (X^? = Cl), [Cr(NH₃)₆]I₂ (X^? = I), [Cr(NCS)₃(NH₃)₃] (X^? = SCN) and [Cr(L-ala)₃] (X^? = NO₃). In those matrix reactions, the ease of anion coordination was: SCN^? > Cl^? > I^? > alanine. For the synthesis of tris(alaninato)chromium(III) complex the most desirable starting complex was [Cr(NH₃)₆](NO₃)₃.The solid state reaction between [Cr(en)₃]X₃ type complexes and NH₄X (X^? = F, Cl, Br, I and SCN), KX (X^? = Cl, Br and I), and NaSCN have been reported by Wendlandt and Stembridge¹. They reported that the reaction product in most cases, was cis-[Cr(en)₂Y₂]X, where Y and X are the same or different anions, depending upon the matrix material employed and the thermal matrix method appears to be a useful new route for the synthesis of bis(ethylendiamine(chromium(III) complexes.In the previous paper², the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-amino acids has been utilized in the preparation of tris(amino acidato)chromium(III) complexes. The preparation of [Cr(L-ala)₃] by the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-alanine have been reported. No studies on the effect of the counter-ion have been reported.In this paper, various hexaamminechromium(III) complexes, [Cr(NH₃)₆]X₃ (X^? = Cl, I, SCN and NO₃), were heated with L-α-alanine under continuous rise in temperature and under isothermal heating at 150°C for studies on the ease of anion coordination. It will seen that the anion which replaces the ammonia in the hexaamminechromium(III) complex comes from either the alanine or counter-ion.