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The notion of a simple ordered state implies homogeneity. If the order is established by a broken symmetry, elementary Landau theory of phase transitions shows that only one symmetry mode describes this state. Precisely at points of phase coexistence domain states formed of large regions of different phases can be stabilized by long range interactions. In uniaxial antiferromagnets the so-called metamagnetism is an example of such a behavior, when an antiferromagnetic and field-induced spin-polarized paramagnetic/ferromagnetic state co-exist at a jump-like transition in the magnetic phase diagram. Here, combining experiment with theoretical analysis, we show that a different type of mixed state between antiferromagnetism and ferromagnetism can be created in certain acentric materials. In the small-angle neutron scattering experiments we observe a field-driven spin-state in the layered antiferromagnet Ca3Ru2O7, which is modulated on a scale between 8 and 20 nm and has both antiferromagnetic and ferromagnetic parts. We call this state a metamagnetic texture and explain its appearance by the chiral twisting effects of the asymmetric Dzyaloshinskii-Moriya (DM) exchange. The observation can be understood as an extraordinary coexistence, in one thermodynamic state, of spin orders belonging to different symmetries. Experimentally, the complex nature of this metamagnetic state is demonstrated by measurements of anomalies in electronic transport which reflect the spin-polarization in the metamagnetic texture, determination of the magnetic orbital moments, which supports the existence of strong spin-orbit effects, a pre-requisite for the mechanism of twisted magnetic states in this material., Comment: Supplementary materials included

A family of lanthanoid(III) hexafluoroarsenates(V), La (AsF 6 ) 3 , LnF(AsF 6 ) 2 , Ln = Ce–Er, and Ln 2 F 3 (AsF 6 ) 3 , Ln = Tm, Yb, Lu, has been stabilized with some fluoro bases as additional ligands forming new compounds: La(HF) 2 (AsF 6 ) 3 , La(XeF 2 ) 2.5 (AsF 6 ) 3 and Ln(AsF 3 ) 3 (AsF 6 ) 3 , Ln = Ce, Pr. La(HF) 2 (AsF 6 ) 3 was prepared by solvothermal reaction in AsF 5 above its critical temperature, while syntheses of other compounds were carried out in anhydrous hydrogen fluoride (aHF) as a solvent at ambient temperature. When Ln 2 O 3 were used as starting compounds in the AsF 5 /aHF superacid medium the oxonium compounds of the type (H 3 O) x Ln y F z (AsF 6 ) x +3 y − z were synthesized. The crystal structures of (H 3 O) 8 La 2 F(AsF 6 ) 13 , (H 3 O) 4 La 2 F(AsF 3 ) 2 (AsF 6 ) 9 , La(HF) 2 (AsF 6 ) 3 and La(XeF 2 ) 2.5 (AsF 6 ) 3 exhibit low-dimensional structural features, while the structure of Ln(AsF 3 ) 3 (AsF 6 ) 3 (Ln = Ce, Pr) shows a three-dimensional network. In the structure of La(HF) 2 (AsF 6 ) 3 bonding interaction between HF and a metal centre is described for the first time.

Chlorine NQR studies of solid nitrosyl chloride NOC1 between 110 and 212 K are reported. In the temperature dependence an order-disorder phase transition near 145 K, found by X-ray diffraction, is confirmed. Unusual hysteretic NQR signal behaviour indirectly proves also the low temperature phase transition below 100 K. In the measured temperature region fast relaxing mechanisms are present. The upper limit of the expected 14N NQR frequency is estimated using the Townes-Dailey approach.

The filled skutterudite compound CePt(4)Ge(12) is situated close to the border between the intermediate valence of Ce and heavy-fermion behavior. Substitution of Ge by Sb drives the system into a strongly correlated and, ultimately, upon further increasing the Sb concentration, an antiferromagnetically ordered state. Our experiments evidence a delicate interplay of emerging Kondo physics and the formation of a local 4f moment. An extended non-Fermi-liquid region, which can be understood in the framework of a Kondo-disorder model, is observed. Band-structure calculations support the conclusion that the physical properties are governed by the interplay of electron supply via Sb substitution and the concomitant volume effects.

Electronic, magnetic, and transport properties of the filled platinum-germanium skutterudite CePt₄Ge₁₂ are investigated. High resolution x-ray absorption spectroscopy measurements at the cerium L(III) edge demonstrate that CePt₄Ge₁₂ in this compound has a temperature-independent valence close to three. However, magnetic susceptibility, thermopower, Hall effect, and electronic specific heat reveal a broad maximum at Tmax D 65-80 K, suggesting the presence of valence fluctuations. The Sommerfeld coefficient γ = 105 mJ mol⁻¹ K⁻², deduced from specific heat, indicates moderately enhanced band masses for CePt₄Ge₁₂. We discuss these findings and conclude that CePt₄Ge₁₂ represents a system at the border between intermediate valence (IV) and Kondo lattice behavior. In addition, the lattice specific heat and the thermal conductivity are discussed with respect to the vibrational dynamics of Ce in the [Pt₄Ge₁₂] framework.

At high temperatures Sr2MnO4-y crystallizes in the K2NiF4 structure with anion defects. X -ray structure determination in space group I 4/m m m (No. 139) with a = 380.58(3), c = 1253.19(11) pm reveals the composition Sr2MnO3.84±0.05 for a single crystal prepared under argon at 1510 °C. The oxygen deficiency is restricted to the basal oxygen atoms in the perovskite layer. The X -ray experiment shows a statistical distribution of the defects. They lead to a distorted tetragonal pyramidal coordination of the Mn3+ ions.

The single phase clathrate-I Ba(8)Ge(43)square(3) (space group Ia3d (no. 230), a = 21.307(1) A) was synthesized by quenching the melt between cold steel plates. Specimens for physical property measurements were characterized by microstructure analysis and X-ray diffraction on polycrystalline samples as well as single crystals. Transport properties including thermopower, electrical resistivity, thermal conductivity and specific heat were investigated in a temperature range of 2-673 K. The electrical resistivity exhibits a metal-like temperature dependence below 300 K turning into a semiconductor-like behaviour above 300 K. The analysis of the specific heat at low temperature indicates a finite density of states at the Fermi level, thus corroborating the metallic character below 300 K. The temperature dependence of the specific heat was modelled assuming Einstein-like localized vibrations of Ba atoms inside the cages of the Ge framework. A conventional crystal-like behaviour of the thermal conductivity with a low lattice contribution (kappa(l)(300 K) = 2.7 W m(-1) K(-1)) has been evidenced.

Arsenic NQR in Co(AsF6)2.2AsF3 reveals three lines: one near 122 MHz and two near 50 MHz. Relations of the spectral lines to the structure and to thermal vibrations are discussed. Possible influence of paramagnetic Co is examined.

From stoichiometric amounts of LaF3 and anhydrous hydrogen fluoride La(HF)2(AsF6)3 was prepared under solvothermal conditions in AsF5 above its critical temperature. The compound crystallizes in space group Pnma (No. 62) with a = 1060.9(2) pm, b = 1726.2(5) pm, c = 770.0(2) pm, and Z = 4 at 293 K. The structure was determined from single-crystal data and shows 10 fluorine atoms connected to the La center. Two of these ligands are provided by HF molecules, a connectivity that was never observed before. All other fluorine ligands are provided by AsF6 units which are bridging between La atoms. In this way infinite slabs are formed which are connected via hydrogen bonds only.

The crystal structure of dichlorine oxide is reported. Cl2O crystallizes in the tetragonal space group I41/amd with a = 772.46(5) pm, c = 926.06(7) pm, and Z = 8 at 90 K. Basically a molecular structure (d(O–Cl) = 170.92(4) pm) with weak secondary Cl–O interactions (d(O … Cl) = 279.86(4) pm) results in a distorted tetrahedral coordination of the oxygen atom. Cl2O is isostructural to the high-pressure modification of water, ice VIII.

Nitrosyl chloride NOC1 has previously mainly been studied in the gaseous state by different methods, e. g. the microwave technique [1, 2]. It is suitable as a model compound for studying the N 0 and N-Cl chemical bonding. The gas phase investigations indicate a considerable degree of ionic character of the N-Cl bond [3]. Vibrational spectra in the solid [4, 5] show an even increased ionicity. and below 85 K the appearance of new low frequency Raman lines suggests a solid phase with completely ionized Cl atoms and NO groups [5]. Because of the reactivity of NOC1. samples are usually kept in sealed glass tubes at lower temperatures. At room temperature the vapor pressure rises to about 2 bars and the compound slowly decomposes. The red liquid crystallizes at 212 K to ruby-red crystals of space group Cmcm. Upon cooling the color gradually lightens, and at liquid nitrogen temperature the material is said to change into bright-yellow microcrystalline "snow"' [5], The facts mentioned above, and recent X-ray diffraction measurements [6| show that this compound deserves more attention. We have undertaken Cl NQR investigations in order to learn more about the N-Cl and N 0 chemical bonding in solid NOC1. where there are also indications of interesting structural transformations.

Bis[(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane-κ 2 N,κ 6 )sodium] dodeca-μ-chlorohexamethoxy-1κO,2κO,3κO,4κO,5κO,6κ0-octahedrohexatantalate-methanol (1/6), [Na(C 18 H 36 N 2 O 6 )] 2 -[Ta 6 Cl 12 (CH 3 O) 5.4 (OH) 0.6 ].6CH 3 OH, is built of (C 18 H 36 N 2 O 6 Na) + cations, [Ta 6 Cl 12 (OCH 3 /lOH) 6 ] 2- anions and solvating methanol molecules linked by hydrogen bridges to the anions. The octahedral [Ta 6 Cl 12 ] 4+ cluster unit exhibits two slightly different Ta-Ta distances of 2.978 (1) and 2.987 (1) A

The salts [18-crown-6-K](4)[Sn(4)Se(10)].5en and [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF were isolated upon addition of THF to the ethylenediamine (en) extracts of the alloys KSn(0.90)Se(1.93) and K(4)Sn(4)Te(10) that had been extracted in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane). The Sn(4)Te(10)(4-) anion has been structurally characterized for the first time by a single-crystal X-ray diffraction study of [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF: P2(1)/n, a = 22.420(5) A, b = 19.570(4) A, c = 24.680(5) A, beta = 96.90(3)(o), Z = 4, and R(1) = 0.0468 at -183 degrees C. In addition to Si(4)Te(10)(4-) and Ge(4)Te(10)(4-), the Sn(4)Te(10)(4-) anion represents the only other known group 14 adamantanoid telluride. The X-ray crystal structure determination of the related [18-crown-6-K](4)[Sn(4)Se(10)].5en salt has also been determined: P2(1)/n, a = 22.003(2) A, b = 18.966(2) A, c = 24.393(2) A, beta = 97.548(8)(o), Z = 4, and R(1) = 0.0843 at -123 degrees C. The anion geometries are of the adamantanoid type where the Sn(IV) atoms occupy the bridgehead positions and the chalcogen atoms occupy the bridging and terminal sites. The energy minimized geometries of Sn(4)Ch(10)(4-) have also been determined using density functional theory (DFT). Mayer bond order analyses, Mayer valencies, and empirical bond valencies indicate that the terminal Sn-Ch bonds have significant multiple bond character, with the terminal Sn-Se bond having more multiple bond character than the terminal Sn-Te bond. The vibrational frequencies of the Sn(4)Se(10)(4-) and Sn(4)Te(10)(4-) anions have been calculated using DFT methods, allowing the Raman spectrum of Sn(4)Se(10)(4-) to be fully assigned.

The salts [AsX4][As(OTeF5)6] and [AsBr4][AsF(OTeF5)5] (X = Cl, Br) have been prepared by oxidation of AsX3 with XOTeF5 in the presence of the OTeF5 acceptors As(OTeF5)5 and AsF(OTeF5)4. The mixed salts [AsCl4][Sb(OTeF5)6-nCl(n-2)] and [AsCl4][Sb(OTeF5)6-nCl(n)] (nor = 2) have also been prepared. The AsBr4+ cation has been fully structurally characterized for the first time in SO2ClF solution by 75As NMR spectroscopy and in the solid state by a single-crystal X-ray diffraction study of [AsBr4][AsF(OTeFs)5]: P1, a = 9.778(4) A, b = 17.731(7) A, c = 18.870(8) A, alpha = 103.53(4)degrees, beta = 103.53(4) degrees, gamma = 105.10(4) degrees, V = 2915(2) A3, Z = 4, and R1 = 0.0368 at -183 degrees C. The crystal structure determination and solution 75As NMR study of the related [AsCl4][As(OTeF5)6] salt have also been carried out: [AsCl4][As(OTeF5)6], R3, a = 9.8741(14) A, c = 55.301(11) A, V= 4669(1) A3, Z = 6, and R1 = 0.0438 at -123 degrees C; and R3, a = 19.688(3) A, c = 55.264(11) A, V= 18552(5) A3, Z = 24, and R1 = 0.1341 at -183 degrees C. The crystal structure of the As(OTeF5)6- salt reveals weaker interactions between the anion and cation than in the previously known AsF6- salt. The AsF(OTeF5)5- anion is reported for the first time and is also weakly coordinating with respect to the AsBr4+ cation. Both cations are undistorted tetrahedra with bond lengths of 2.041(5)-2.056(3) A for AsCl4+ and 2.225(2)-2.236(2) A for AsBr4+. The Raman spectra are consistent with undistorted AsX4+ tetrahedra and have been assigned under Td point symmetry. The 35Cl/37Cl isotope shifts have been observed and assigned for AsCl4+, and the geometrical parameters and vibrational frequencies of all known and presently unknown PnX4+ (Pn = P, As, Sb, Bi; X = F, Cl, Br, I) cations have been calculated using density functional theory methods.

The Tl5Se5(3-) anion has been obtained by extracting KTlSe in ethylenediamine in the presence of 2,2,2-crypt. The salt, (2,2,2-crypt-K+)3Tl5Se5(3-), crystallizes in the triclinic system, space group P1, with Z = 2 and a = 11.676(2) A, b = 16.017(3) A, c = 25.421(5) A, alpha = 82.42(3) degrees, beta = 88.47(3) degrees, gamma = 69.03(3) degrees at -123 degrees C. Two other mixed oxidation state TlI/TlIII anions; Tl4Se5(4-) and Tl4Se6(4-), have been obtained by extracting KTlSe into liquid NH3 in the presence of 2,2,2-crypt and have been characterized in solution by low-temperature 77Se, 203Tl, and 205Tl NMR spectroscopy and were shown to exist as a 1:1 equilibrium mixture at -40 degrees C. The couplings, 1J(203,205Tl-77Se) and 2J(203,205Tl-203,205Tl), have been observed for Tl4Se5(4-) and Tl4Se6(4-) and have been used to arrive at the solution structures of both anions. Structural assignments were achieved by detailed analyses and simulations of all spin multiplets that comprise the 205,203Tl NMR spectra and that arise from natural abundance 205,203Tl and 77Se or enriched 77Se isotopomer distributions. The structures of all three anions are based on a Tl4Se4 cube in which Tl and Se atoms occupy alternate corners. There are one and two exo-selenium atoms bonded to thallium in Tl4Se5(4-) and Tl4Se6(4-), respectively, so that these thalliums are four-coordinate and possess a formal oxidation state of +3 and the remaining three-coordinate thallium atoms are in the +1 oxidation state. The structure of Tl5Se5(3-) may be formally regarded as an adduct in which Tl+ is coordinated to the unique exo-selenium and to two seleniums in a cube face containing the TlIII atom. The Tl4Se5(4-), Tl4Se6(4-), and Tl5Se5(3-) anions and the presently unknown, but structurally related, Tl4Se4(4-) anion can be described as electron-precise cages. Ab initio methods at the MP2 level of theory show that Tl4Se5(4-), Tl4Se6(4-), and Tl5Se5(3-) exhibit true minima and display geometrical parameters that are in excellent agreement with their experimental cubanoid structures, and that Tl4Se4(4-) is cube-shaped (Td point symmetry). The gas-phase energetics associated with plausible routes to the formation and interconversions of these anions have been determined by ab initio methods and assessed. It is proposed that all three cubanoid anions are derived from the known Tl2Se2(2-), TlSe3(3-), Se2(2-), and polyselenide anions that have been shown to be present in the solutions they are derived from.

AlBCsHO9P2, monoclinic, P121/c1 (No. 14), a = 9.208(2) A, b = 8.6957(9) A, c = 9.469(1) A, β = 104.189(6)°, V = 735.0 A 3 , Z =4 ,Rgt(F) = 0.036, wRref(F 2 ) = 0.087, T = 295 K.

Gd4I5Si and Gd3I3Si were prepared from gadolinium, GdI3 and silicon at 1050–1100 °C in tantalum ampoules. The crystal structures were determined and are isotypic with Y4I5C and Gd3Cl3C (for Gd4I5Si C2/m, Z = 2, a = 18.917 5(19) A , b = 4.1966(4) A , c = 8.7099(9) A , β = 103.298(8)°, R = 2.23% and R w = 1.81% ; for Gd3I3Si, I4132, Z = 8, a = 12.052(2) A , R = 3.74% and R w = 3.33% ). Gd4I5Si and Gd3I3Si have cation-deficient NaCl structures and contain infinite one-dimensional chains and a three-dimensional network of edge-sharing silicon-centred gadolinium octahedra respectively. Results of structural analyses and extended Huckel molecular orbital band calculations are presented. The importance of the ionic interactions and the metal-metal and metal-silicon bonding is discussed as is the dimensionality of the structure in regard to the optimization of the size of the Gd6 octahedra with the interstitial atom.

Gd4I5Si and Gd3I3Si were prepared from gadolinium, GdI3 and silicon at 1050–1100 °C in tantalum ampoules. The crystal structures were determined and are isotypic with Y4I5C and Gd3Cl3C (for Gd4I5Si C2/m, Z = 2, a = 18.917 5(19) A , b = 4.1966(4) A , c = 8.7099(9) A , β = 103.298(8)°, R = 2.23% and R w = 1.81% ; for Gd3I3Si, I4132, Z = 8, a = 12.052(2) A , R = 3.74% and R w = 3.33% ). Gd4I5Si and Gd3I3Si have cation-deficient NaCl structures and contain infinite one-dimensional chains and a three-dimensional network of edge-sharing silicon-centred gadolinium octahedra respectively. Results of structural analyses and extended Huckel molecular orbital band calculations are presented. The importance of the ionic interactions and the metal-metal and metal-silicon bonding is discussed as is the dimensionality of the structure in regard to the optimization of the size of the Gd6 octahedra with the interstitial atom.

Der Anwendungsbereich von Inertgasen zur Explosions- und Oxidationsverhutung bei der Herstellung, Verarbeitung, Lagerung oder beim Transport chemischer Produkte hat sich in letzter Zeit standig erweitert, so das fur viele Betriebe eine Eigenerzeugung dieser Gase lohnend erscheint. Uber die einzelnen Anwendungsgebiete und die derzeit bekannten Verfahren und Anlagen zur Gewinnung von Inertgasen gibt dieser Beitrag einen Uberblick, in den auch die Verwendung und Herstellung von Wasserstoff als Reaktionsgas mit einbezogen wurde.

CsGaHO10P3, monoclinic, P121/n1 (No. 13), a = 8.843(1) Å, b = 4.9523(5) Å, c = 11.084(1) Å, β = 108.793(6)0, V = 459.5 Å3, Z = 2, Rgt(F) = 0.042, wRref(F2) = 0.123, T = 295 K.