NaF-CaF<Subscript>2</Subscript>-YbF<Subscript>3</Subscript> phase diagram

Vertical sections CaF₂-Na_0.4Yb_0.6F_2.2 and NaF-Ca_0.75Yb_0.25F_2.25 of the system NaF-CaF₂-YbF₃ were studied by differential thermal analysis. A fluorite solid solution belt between phases of variable composition Ca_1?x Yb _x F_2+x and Na_0.5?x Yb_0.5+x F_2+2x was discovered. A liquidus-surface projection was constructed. The solidification character of the solid solution is unfavorable for growth of optical-quality ternary mixed crystals.     

Phase diagram of the system CaF2-GdF3

A phase diagram of the system CaF₂-GdF₃ was studied by thermal and X-ray analysis. Two wide domains of solid solutions based on CaF₂ and a high-temperature modification of α-GdF₃ (LaF₃-structural type) are present in this system. Two maxima were found on the melting curves of the Ca_1?xGd_xF_2+x and α-(Gd_1?yCa_yF_3?y solid solutions, at 1428 ± 10? (5 mole % GdF₃) and 1282 ± 5? (85 mole % GdF₃), respectively. The coordinates of the eutectic are 60 mole % GdF₃ and 1233 ± 5?.

     

Thermal transformation of quaternary compounds in NaF–CaF2–AlF3 system

Details of quaternary compounds formation in the system NaF–CaF₂–AlF₃ are specified. To achieve this aim, the samples of phases NaCaAlF₆ and Na₂Ca₃Al₂F₁₄ have been obtained by high-temperature solid-phase synthesis. Their thermal behavior when heated up to 800 °C has been studied using the methods of high-temperature X-ray diffraction (XRD) and thermal analysis (TA). The system under consideration can be regarded as a quasibinary section CaF₂–NaAlF₄, where at T=745–750 °C invariant equilibrium is implemented with the phases CaF₂–NaCaAlF₆–Na₂Ca₃Al₂F₁₄–(liquid melt)–(NaAlF₄). The peculiarity of the equilibrium is NaAlF₄ metastability at normal pressure. Below the equilibrium temperature the quaternary phase Na₂Ca₃Al₂F₁₄ is stable and NaCaAlF₆ above this temperature. The phase NaCaAlF₆ fixed by rapid quenching from high temperatures and when heated up to 640 °C decomposes, yielding Na₂Ca₃Al₂F₁₄. Further heating in vacuum at temperature up to 740 °C results in decomposition of Na₂Ca₃Al₂F₁₄ into CaF₂ and Na₃AlF₆. The expected reverse transformation of Na₂Ca₃Al₂F₁₄ into NaCaAlF₆ has not been observed under experimental conditions. Transformations in bulk samples reveal direct and reverse transformation of quaternary phases.

Synopsis

Thermal transformation of the quaternary compounds in system (NaF–CaF₂–AlF₃) was investigated using high-temperature X-ray diffraction (XRD) and thermal analysis (TA). In the system the invariant equilibrium is implemented with the phases CaF₂–NaCaAlF₆–Na₂Ca₃Al₂F₁₄–(liquid melt)–(NaAlF₄) at T=745–750 °C.     

Poly(vinylidene fluoride) as a reagent for the synthesis of K2NiF4-related inorganic oxide fluorides

In this paper we report an improved route to the synthesis of K₂NiF₄-related inorganic oxide fluorides, such as Sr₂TiO₃F₂ and Ca₂CuO₂F₂ using low-temperature fluorination of precursor oxides with poly(vinylidene fluoride). Use of this fluorinating agent results in high quality samples, without SrF₂ or CaF₂ or other impurities, which are commonly seen for alternative fluorination routes.     

Low-temperature phase formation in CaF<Subscript>2</Subscript>–HoF<Subscript>3</Subscript> system

Phase formation in CaF₂–HoF₃ system has been studied by coprecipitation followed by X-ray powder diffraction. Aqueous nitrate solutions have been used as initial substances, while hydrofluoric acid has been employed as fluorinating agent. Formation of hydrated nanophases: solid solution Ca_1–x Ho _x F_{2 + x} (х ≤ 0.1) and HoF3 has been revealed. Dehydration proceeds on heating to 600°C.     

Fluordiazadiphosphetidine, 3. Mitt.: Die thermische Behandlung von 2,2,2,4,4,4-Hexafluoro-1,3-dimethyl-1,3,2,4-diazadiphosphetidin unter Druck in Gegenwart von Phosphor(V)fluorid und Alkalimetallfluoriden

Prolonged heating of (CH₃NPF₃)₂ in a sealed tube at 120°C yields (CH₃N)₄P₃F₇ and PF₅. Under the experimental conditions these compounds react to (CH₃N)₄P₃F₆ ⁺PF₆ ^–. Reaction of (CH₃NPF₃)₂ in the presence of PF₅ leads to a marked decrease in the formation of the ionic compound. The influence of the fluoride donating saltsMF (M=Li, Na, K, Cs) is investigated.

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Früher: Alkyliminophosphorsäuretrihalogenide, 1. und 2. Mitt.     

Magnetische Eigenschaften der Verbindungen BaMF4 und Pb2 MF6 (M=Mn,Fe, Co,Ni, Cu,Zn)

Zusammenfassung In den beiden untersuchten Doppelfluorid-Serien, BaMF₄ und Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn), zeigen die Verbindungen des Cu und des Zn ein anderes Verhalten als die übrigen. Die Zn-Verbindungen sind diamagnetisch, die Cu-Verbindungen paramagnetisch. Pb₂CuF₆ befolgt dasCuriesche Gesetz, während BaCuF₄ eineCurie-Weiss-Abweichung unterhalb 212 K aufweist.Im untersuchten Temperaturbereich zeigt sich für alle anderen Verbindungen, mit Ausnahme von Pb₂FeF₆, Antiferromagnetismus.

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Magnetic properties of the compounds BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn)

Two series of double fluorides, BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn) have been studied, the compounds of Cu and Zn differing in behaviour from the others. The Zn componds are diamagnetic, the Cu compounds paramagnetic. Pb₂CuF₆ conforms toCurie's law while BaCuF₄ exhibits aCurie-Weiss deviation below 212° K.With the exception of Pb₂FeF₆, all the other compounds show antiferromagnetism in the studied temperature range.

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Herrn Prof. Dr.Hans Nowotny ergebenst gewidmet.     

Untersuchung der magnetostrukturellen Eigenschaften gemeinsam gefällter Hydroxide von Cd2+, Ni2+ und Fe3+

Zusammenfassung Aus einer Reihe gemeinsam gefällter und in siedendem Wasser gealterter Hydroxide, deren Mischungsverhältnis die Bildung von Cd _x Fe_1–x [Ni_1–x Fe_1+x ]O₄-Ferriten möglich machte, wurden Präparate erhalten, welche charakteristische Sättigungs-Magnetísierungskurven zeigen. Röntgenographische Analyse und magnetische Untersuchungen zeigten, daß der primäre Ferromagnetismus dieser Präparate dem -Fe₂O₃ zuzuschreiben ist.

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Studies of the magnetostructural properties of coprecipitated hydroxides of Cd²⁺, Ni²⁺ and Fe³⁺

From a series of coprecipitated hydroxides, aged by boiling in water, and in which the mixing proportions enabled the formation of Cd _x Fe_1–x [Ni_1–x Fe_1+x ]O₄-ferrites, preparations were obtained which show characteristic saturation magnetization curves. X-ray analysis and magnetic studies showed that the primary ferromagnetism of these preparations must be assigned to -Fe₂O₃.

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Strukturelle Übergänge zwischen Phosphiden,Arseniden und Arsenophosphiden der ZusammensetzungM 2P,M 2As undM 2(P1—xAsx)

Zusammenfassung Phasen der ZusammensetzungM ₂P,M ₂As undM ₂(P_1-xAs_x) wurden untersucht. Dabei istM ein Übergangsmetall (M=Cr, Mn, Fe, Co, Ni) oder ein Gemisch solcher Metalle. Es treten tetragonale, hexagonale sowie orthorhombische Strukturtypen auf, die sich alle auf ein rhomboedrisches Grundelement zurückführen lassen, in dem die Metallatome pyramidal oder tetraedrisch von Metalloidatomen umgeben sind. Dabei zeigt sich, daß das Auftreten der Strukturen nicht mit der mittleren Zahl der 3d-Elektronen des Kationenanteils zusammenhängt. Ein Strukturwechsel tetragonal hexagonal orthorhombisch läßt sich hingegen auf steigende Wechselwirkung zwischen den Metallatomen zurückführen.

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Structural transitions between phosphides, arsenides and arsenophoshides of the composition M₂ P, M₂ As and M₂(P _1—xAs_x)

A study has been made of phases of the compositionM ₂P,M ₂As, andM ₂(P_1-xAs_x) whereM is a transition metal (Cr, Mn, Fe, Co, Ni) or a mixture of such metals. Tetragonal, hexagonal and orthorhombic structural types occur, which can all be referred to a rhombohedral primary structure, with metalloid atoms in a pyramidal or tetrahedral arrangement about the metal atoms. It is found that the occurrence of the structures is not related to the average number of 3d electrons of the cationic part, but that a structural variation tetragonal hexagonal orthorhombic can be ascribed to increasing interaction between the metal atoms.

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Gewidmet Herrn Prof. Dr.H. Nowotny in Bewunderung fü das Werk, das die Wiener Schule geschaffen hat.     

Recherche de matériauxa`conductivitéionique ame´liore´e de´rivant des hydrurofluorures de calcium CaF2−xHx: conductivite´ ionique des phases Ca1−yNay(F2−xHx)1−y/2

The doping of CaF_2?xH_x hydridefluorides by aliovalent ions is studied, the aim being the preparation of materials of improved ionic conductivity. It is shown that doping by monovalent Na⁺ ions is possible. Three hydrogen-rich phases, formulated Na_yCa_1?y(F_2?xH_x)_1?y/2 have been studied. Their conductivity is mainly ionic, but, compared with the same doping in CaF₂, the conductivity enhancement is low. This result is interpreted from energetic and structural considerations.     

Strukturuntersuchungen an Usoviten: Ba2CaMIIV2F14 (MIII = Mn,Fe), Ba2CaMnFe2F14 und Ba2CaCuM2IIIF14 (MIII = Mn,Fe, Ga)

Structural Studies with Usovites: Ba₂CaM^IIV₂F₁₄ (M^III = Mn, Fe), Ba₂CaMnFe₂F₁₄ and Ba₂CaCuM₂^IIIF₁₄ (M^III = Mn, Fe, Ga). Single crystals of six compounds Ba₂CaM^IIM₂^IIIF₁₄ were prepared to refine their usovite type structure (space group C2/c, Z = 4) using X‐ray diffractometer data. The cell parameters of the phases studied with M^IIM₂^III= MnV₂, FeV₂, CuMn₂, MnFe₂, CuFe₂ und CuGa₂ are within the range 1374≤a/pm≤1384, 534≤b/pm≤542, 1474≤c/pm≤1510, 91, 3≤ß/°≤93, 2. The atoms Ca and M^II are incompletely ordered on the 8‐ and 6‐coordinated positions, 4e and 4b, respectively. In the case of Ba₂CaFeV₂F₁₄ and Ba₂CaCuGa₂F₁₄ there is reciprocal substitution (x≈0, 1): (Ca_1‐xM_x^II) (4e) and (M_1‐x^IICa_x) (4b). In the case of the other usovites Ca‐enriched phases Ba₂Ca(M_1‐y^IICa_y)M₂^IIIF₁₄ occured (up to y≈0, 35), exhibiting partial substitution at the octahedral position (4b) only, showing a corresponding increase in M^II‐F distances. The distortion of [M^IIF₆] and [M^IIIF₆] octahedra within the structure is considerably enhanced on replacement by Cu^II and Mn^III. The results of powder magnetic susceptibility measurements of Ba₂CaMnV₂F₁₄ and Ba₂CaFeV₂F₁₄ (T_N≈7K) are reported.     

Phase diagram of the NaF–CaF<Subscript>2</Subscript> system and the electrical conductivity of a CaF<Subscript>2</Subscript>-based solid solution

The phase diagram of the NaF–CaF₂ system was studied by thermal analysis and X-ray powder diffraction analysis with the determination of the chemical composition. The system was found to be of the eutectic type. A narrow range of the existence of solid solution Ca_1–xNa_xF_2–x was established. The NaF solubility reaches a maximal value of x = 0.035 at 1200 ± 50°C (the temperature at which there is a diffuse phase transition in fluorite). At 920 ± 25°C, the NaF solubility reaches a minimum (<0.4 mol %) and increases again to 2.2 ± 0.2 mol % at a eutectic temperature (818°C). The ionic conductivity increases by three orders of magnitude after adding NaF to CaF₂.     

Farbe und Konstitution bei anorganischen Feststoffen, 15. Mitt.: Die Lichtabsorption des zweiwertigen Kobalts in Silikaten vom Olivintypus

Zusammenfassung Mischkristalle Co _x Mg_1-x CaSiO₄ (I) und Co _x Mg_2-x SiO₄ (II), in denen sich das Mg²⁺ vollständig durch Co²⁺ ersetzen läßt, wurden röntgenographisch und spektralphotometrisch untersucht, desgleichen Mischkristalle {CoCaSiO₄+y Co₂SiO₄} (III), <y0,1>. In I befindet sich das Co²⁺ in den triklin verzerrten OktaederpositionenM _i , in II und III außerdem in den monoklin verzerrten OktaederlückenM _s des Olivingitters (M _i M _s SiO₄).Beim Einbau von Co²⁺ in Mg₂SiO₄ werden die kleinerenM _i O₆-Polyeder bevorzugt besetzt und aufgeweitet. Die Absorptionsspektren des Co _s ²⁺ von II und III konnten ermittelt werden, indem man die überlagerte Lichtabsorption des Co _i ²⁺ durch ein Näherungsverfahren eliminierte. Beim Übergang Co _s ²⁺(II) Co _s ²⁺(III) wird eine beträchtliche IR-Verschiebung beobachtet; sie ist die Folge der Aufweitung derM _s O₆-Polyeder bei der Substitution von Mg²⁺ (bzw. Co²⁺ durch Ca²⁺.Folge der starken Verzerrung der Koordinationsoktaeder im Olivingitter, deren Konstitution ausführlich beschrieben wird, ist eine Verbreiterung und Aufspaltung der Absorptionsbanden. Während der Feldstärkenparameter für Co _i ²⁺ in den Co-haltigen Olivinphasen mit (Co²⁺) von Co _x Mg_1-x O vergleichbar ist. resultieren für Co _s ²⁺ auffallend niedrige -Werte.

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Mixed crystals Co _x Mg_1–x CaSiO₄ (I)<0,1x1,0>, Co _x Mg_2–x SiO₄ (II) <0,05x2,0>, and {CoCaSiO₄+yCo₂SiO₄} (III) –1). These phases crystallize in the olivine structure (M _i MM _s SiO₄) containing two differently distorted octahedral sites (M _i of triclinic andM _s of monoclinic symmetry).In I the Co²⁺ are incorporated in the intersticesM _i , in II and III in the intersticesM _s in addition. In II—for small values ofx—the smallerM _i O₆-polyhedra are occupied preferably by Co²⁺ and also widened. The spectra for Co _s ²⁺ of II and III could be obtained by eliminating the superimposed absorption of the Co _i ²⁺ using an approximative substraction method. Going from Co _s ²⁺(II) to Co _s ²⁺(III) produces a considerable shift of the absorption bands towards IR as a consequence of the expansion of theM _s O₆-polyhedra caused by the large Ca²⁺ in III.The considerable distortion of the coordination octahedra in the olivine lattice causes a broadening and splitting of the absorption bands. Whereas the ligand-field-parameter of Co²⁺ in theM _i -sites ofM _i M _s SiO₄ may be compared to (Co²⁺) of Co _x Mg_1–x O, remarkably low -values are observed for Co _s ²⁺.

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14. Mitt.:O. Schmitz-DuMont, H. Fendel, M. Hassanein undHelga Weissenfeld; Mh. Chem.97, 1660 (1966).     

The Raman spectrum of tetragonal Eu3+CaF2

The Raman spectrum of a tetragonal single crystal of the compound Eu_xCa_1-(3/2)x F₂(where x = 0.002) is reported. The main features of the spectrum are the ⁷F₀ - ⁷F₁ and ⁷F₀ → ⁷F₂ electronic transitions of Eu³⁺ ions located at a site of C₂ symmetry and vibrational transitions which involve movements of the europium ion. The characteristic phonon band of cubic CaF₂ is for the rare-earth doped crystal moved to a higher frequency and the corresponding Raman tensor is that for a crystal of tetragonal symmetry.     

Hydrurofluorures ioniques MF2−xHx (M = Sr,Ba): Synthèse et étude structurale par diffraction des neutrons

The study of the substitution of H^? for F^? ions in SrF₂ and BaF₂ has shown the existence of the cubic hydride fluorides MF_2?xH_x (M = Sr, Ba). The variation of the lattice parameter with hydrogen replacement is stronger than it is in the case of CaF_2?xH_x. The upper limit of substitution diminishes for the series calcium, strontium, barium. Neutron diffraction confirms the simple structural model, already proposed for calcium hydride fluoride: a fluorine cubic structure with a statistical distribution of H^? and F^? on 8(c) sites.     

Fluoralkyl-und Fluorarylborazinderivate, 4. Mitt.: γ-Fluororganoborazinderivate und einige β-Fluororganoborazine

Zusammenfassung Neue Pentafluorbenzylborazine wurden durch Reaktion (a) von C₆F₅CN mit B₂H₆, (b) von C₆F₅CH₂NH₃Cl mit BCl₃ und (c) von B-Halogenborazinen mit C₆F₅CH₂MgBr dargestellt. Außerdem wurden neue N--Trifluororganoborazinderivate erhalten. Einige dieser Verbindungen sind weitgehend hydrolysefest. Ihre IR-Spektren werden diskutiert.

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New pentafluorobenzylborazines have been prepared by reacting (a) C₆F₅CN with B₂H₆, (b) C₆F₅CH₂NH₃Cl with BCl₃ and (c) B-halogenoborazine derivatives with C₆F₅CH₂MgBr. New N--trifluoroorganoborazines are described. Some of these compounds show good hydrolytic stability. The IR-spectra are discussed.

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3. Mitt.:A. Meller, M. Wechsberg undV. Gutmann, Mh. Chem.97, 619 (1966).     

Use of ethyl oxamate for syntheses of oxamato(-1) and novel μ-oxamato(-2) complexes

Summary The use of ethyl oxamate for the synthesis of inorganic oxamato complexes is reported. A reaction system leading to the preparation of the novel polymeric -oxamato(-2) complexes [M(oxm)(H₂O)₂] _x (M=Cu, Zn, Cd), [Co(oxm)(H₂O)₂] _x ·0.5xH₂O and [Ni(oxm)(H₂O)₂] _x ·xH₂O is described (H₂ oxm = oxamic acid). Ethyl oxamate can also be used for the preparation of monomeric oxamato(-1) complexes.

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Der Einsatz von Ethyloxamat für die Synthese von Oxamato(-1) und neuen -Oxamato(-2)-Komplexen (Kurze Mitt.)

Zusammenfassung Es wird der Einsatz von Ethyloxamat für die Synthese von anorganischen Oxamato-Komplexen beschrieben. Ein Reaktions-System für die Herstellung von neuen -Oxamato(-2)-Komplexpolymeren: [M(oxm)(H₂O)₂] _x ; (M = Cu, Zn, Cd), [Co(oxm)(H₂O)₂] _x ·0.5xH₂O und [Ni(oxm)(H₂O)₂] _x ·xH₂O, wird vorgestellt. Ethyloxamat kann auch für die Herstellung von monomeren Oxamato(-1)-Komplexen verwendet werden.

     

Metallographische Untersuchungen über das System Ag2Te x Se1−x

Zusammenfassung Das System Ag₂Te _x Se_1–x wurde im Bereich 0<x<1 mit x=0,1 metallographisch untersucht. Zur Entwicklung der Mikrostruktur ist ein Ätzmittel mit der Zusammensetzung HNO₃CH₃COOHH₂O=213 vorgeschlagen worden; auch die Mikrohärte der Proben wurde ermittelt. Auf Grund der Ergebnisse der Röntgen-Phasenanalyse, der Mikrostruktur und Mikrohärte wird bei 120°C die Anwesenheit einer diskontinuierlichen festen Lösung angenommen.

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Metallographic investigation of the system Ag₂Te _x Se_1–x

The system Ag₂Te _x Se_1–x has metallographically been investigated forx from 0 to 1 and x=0.1. For developing the micro-structure, an etching mixture of composition HNO₃CH₃COOHH₂O=213 is proposed. Micro-hardness of the samples also has been established. On the basis of the results from the X-ray-phase-analysis, the micro-structure and micro-hardness, the presence of a discontinous solid solution is assumed at 120°C.

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Synthesis and magnetic properties of the quasi-one-dimensional compound Ca0.83(Cu1−xCox)O2

A new solid solution of the quasi-one-dimensional composite crystal, , has been synthesized under of O₂ at 830°C. The non-doped compound Ca_0.83CuO₂ consists of two interpenetrating monoclinic subsystems of the [Ca] atoms and the edge-shared square planar [CuO₂] chains. Upon increasing x, both the subsystems undergo a phase change from monoclinic to orthorhombic (M-O). The M-O change occurs at x∼0.04 for the [(Cu,Co)O₂] subsystem, while such a change occurs at x∼0.17 for the [Ca] subsystem. Magnetic susceptibility measurements show an evolution from a short-range ordered state near x=0 to a long-range antiferromagnetic state for the samples with x?0.15. The effective magnetic moment μ_eff is found to increase with increasing x from for x=0.10 to for x=0.30, suggesting that the solid solution can be regarded as Ca_0.83[Cu_0.66²⁺Cu_0.34−x³⁺Co_x³⁺]O₂, in which a mixed state of Cu²⁺(S=1/2), Cu³⁺(S=0) and high-spin Co³⁺(S=2) ions is realized.