bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transition Metal Complexes of Ambidinourea and Related Ligands.
Authors: Syamal A. 
Published: March 2015

Copper (II), nickel (II), and palladium (II) complexes of amidinourea are reinvestigated in order to verify their structure. Electronic spectra and magnetic susceptibility measurements have been obtained on the solid complexes. Electronic spectral results indicate the donor strength of amidinourea is comparable to strong field ligands like biuret, biguanide, and I-amidino-O-alkylurea. Infra-red spectral results suggest that the carbonyl group of amidinourea is not involved in coordination and the donor atoms in amidinourea are amide nitrogens. The effect of solvents on the absorption bands is also discussed. The solution absorption spectra of bis (amidinourea) copper (II) chloride in different solvents indicate the following order of decreasing tetragonality:
DMSO &gt; methanol &gt; ethyleneglycol &gt; water.
Darstellung von Trifluorsilylarsan und -phosphan / The Preparation of Trifluorosilylarsine and -phosphine
Authors: Demuth Reinhard 
Published: March 2015

A direct synthesis of the compounds F3SiAsH2 and F3SiPH2 (F3SiPD2) by the reaction of F3SiBr with (CH3)3Sn-AsH2 and (CH3)3Sn-PH2 [(CH3)3Sn-PD2] respectively is reported (yield &gt; 70%).
F3SiBr itself was prepared by the cleavage of (C2H5)2N-SiF3 with HBr. NMR data of the compounds is shown.
Die Komplexbildung zwischen Molybdationen und Perjodsäure V / Formation of Complexes Between Molybdations and Periodic Acid V
Authors: Wiese Günther , Böse Doris 
Published: March 2015

Heteropolyacids, isomolybdates, dilatometric titrations
By dilatometric titrations and a mathematical analysis of the titrations results the chemism of formation of the heteropolyanion [JMo6O24]5- and its protonation was investigated.
Complex Formation Between Imidazole and Nickel(II) Salts
Authors: Jansen J. C. , Reedijk J. 
Published: March 2015

Coordination compounds of formula Ni(Iz)nX2(H2O)m, in which Iz=imidazole, n = 1, 2, 4, 6, m = 0-4, and X = Cl-, Br-, I- and NCS-, are described. The anhydrous compounds are prepared from ethanolic solutions of Iz and nickel(II) salts in stoichiometric amounts in the presence of the dehydrating agent triethylorthoformate. Without this dehydrating agent hydrates are isolated for n = 2,4 and 6 with X = Cl, Br.
The compounds were identified by means of infrared spectra (4000-25 cm-1), ligand-field spectra (35000-4000 cm-1) and X-ray powder diagrams. Compounds of formula [Ni(Iz)6]X2 all contain octahedrally coordinated Ni2+, for which the spectrochemical parameters were obtained. Tetragonal Ni2+ ions occur in [Ni(Iz)4X2] in which X = Cl and NCS, and in [Ni(Iz)4(H2O)2]X2 in which X = Cl and Br. These compounds are paramagnetic and the crystal-field parameters for tetragonal symmetry have been calculated. In [Ni(Iz)4]X2 with X = I and Br, the Ni2+ ions are square-planar coordinated with anions in the second coordination sphere, resulting in orange-coloured diamagnetic compounds.
Anion-bridged distorted octahedrally coordinated Ni2+ ions probably occur in the compounds of formula Ni(Iz)2X2, in which Iz takes the axial positions. Similar structures are suggested for the mono-imidazole compounds, NiIzX2.
Über die Koordinationspolymeren M(II) [Pt(CN)6], I Darstellung, Kristallgitter und Lichtabsorptionsspektren / Coordination Polymers M(II) [Pt(CN)6], I Preparation, Crystal Lattice and Absorption Spectra
Authors: Siebert Hans , Weise Manfred 
Published: March 2015

Hexacyanoplatinates(IV) M(II) [Pt(CN)6] · x H2O (M(II) = Mg, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd; 0 ≦ x ≦ 2) have been prepared. According to their X-ray powder diagrams the compounds crystallize cubic, space group O5
h—Fm3m, Z = 4, with the exception of the Cr and the Cu salt. Due to JAHN-TELLER-distortion of Cr(II) and Cu(II) the latter compounds crystallize tetragonal.
Light absorption spectra of the compounds in the NIR, visible and UV region have been assigned to the d—d transitions of the M(II) electrons in the field of the six N ligands. Crystal field parameters have been determined. In the spectrochemical series, the N atoms of [Pt(CN)6]2— have a position between NH3 and ethylenediamine.
A new simple method to prepare K2[Pt(CN)e] has been developped.
Reactions with 5-Substituted-1,3-thiazolidine-2,4-dithiones Heterodiene Syntheses
Authors: Kassab Nazmi Abd El Latif , Allah Sanaa Osman Abd , Ead Hamed Abd El Reheem 
Published: March 2015

The arylidene derivatives (1) of 1,3-thiazolidine-2,4-dithione undergo 1,4-cycloaddition reaction with acrylonitrile, ethyl acrylate, ω-nitrostyrene, styryl ethyl ketone and N-aryl-maleimides leading to substituted tetrahydrothiopyrano-7 H[2,3-d]thiazole-2thiones (2), (8) and (4).
Grignard reagents effects addition to the double bond of the lateral chain of 1 to yield products proved to have structure 7.
Darstellung, Struktur und einige Reaktionen von Tris(dimethylamino)gallan / Preparation, Structure and Some Reactions of Trisdimethylaminogallane
Authors: Nöth H. , Konrad P. 
Published: March 2015

The aminogallanes Ga[N(CH3)2]3 (1), ClGa[N(CH3)2]2 (2) and Ga[N(Si(CH3)3)2]3 (3) are prepared by reacting GaCl3 with LiN(CH3)2 and NaN[Si(CH3)3]2, respectively. Excess LiN(CH3)2 leads to LiGa[N(CH3)4] which reacts with GaCl3 to yield 1. CS2 inserts into all Ga—N bonds of 1 yielding monomeric Ga[S2CN(CH3)3)2]3 (4).
1 dimerizes via dimethylamino bridges. In contrast, 1H. NMR spectra indicate group exchange for dimeric 2. Assoziation of 3 is prevented due to steric hindrance. The gallium atom in 4 exhibits hexacoordination, and there is evidence for the binding of the (CH3)2NCS2 groups through S atoms only.
Über Reaktionen mit Betain, X1 Die katalytische Hydrierung von Diketo-S-Yliden / Reactions with Betaine, X1 The Catalytic Hydrogenation of Diketo-S-Ylides
Authors: Wittmann Helga , Petio Franz Adolf 
Published: March 2015

3-Hydroxy-3-phenylpropionic Acid Anilide, Catalytic Hydrogenation
The catalytic hydrogenation (20 °C, 760 mm) of dimethylsulfoniumphenacyl-phenylcarbamoylmethylide (1 a) and the nitro derivative (1 b) yields the new β-keto-S-ylides (3 a) and (3 c). At higher temperature and pressure the same reaction gives under loss of dimethylsulfide the propionic acid anilides (2a) and (2b).
Zur Elektronenstruktur hochsymmetrischer Komplexe der Lanthaniden und Actinoiden, I Magnetismus und Schwingungsspektren von Tris(tetraäthylammonium)-hexaisocyanato-ytterbium(III) / The Electronic Structure of Highly-Symmetrical Lanthanide and Actinide Complexes, I Magnetism and Vibrational Spectra of Tris(tetraethylammonium)-hexaisocyanate-ytterbium(III)
Authors: Amberger H.-D. , Fischer R. D. , Rosenbauer G. G. 
Published: March 2015

The results of a combined infrared and Raman-spectroscopic analysis of the compounds [N(C2H5)4]3[Ln(III)(NCO)6] (Ln = Yb, Lu) confirms the assumption that the central ion Ln3+ is octahedrally surrounded by six linear isocyanate ligands. The recently determined temperature dependence of the magnetic susceptibility of the Yb-complex in the range 1.0 < T < 300.2 K is compatible with the crystal field (= CF) splitting pattern: 0 = Ε(Γ6) < Ε(Γ8) < Ε(Γ7) ≪ Ε(Γ'8) < Ε(Γ'7) and a spectroscopic splitting factor |gexp(Γ6)| = 2.576 [i.e. k(tlu) = 0.955].
Using the cubic first-order CF-functions, the energy differences ΔE(Γ8-Γ6) and ΔΕ(Γ7-Γ6) are fixed at 277 ± 10 and 650 ±130 cm-1 respectively. On this basis, the estimated ratio B4°/B6° of the two underlying cubic CF-parameters is discussed in terms of both “electrostatic” and “covalency” effects. This analysis has been used to interpret the paramagnetism of Cs2NaYbCl6 in terms of much larger CF-parameters than previously suggested
Die Kristallstruktur von Thiocyanato(2-dimethylaminoäthanolato)kupfer(II) / The Crystal Structure of Thiocyanato(2-dimethylaminoethanalato)copper(II)
Authors: Haase W. , Mergehenn R. , Krell W. 
Published: March 2015

The crystal structure of the title compound has been determined from three-dimensional X-ray diffractometer data. Crystals are monoclinic, space group P21/c with 8 Cu(C4H10NO)SCN units in a cell of dimensions α = 11.951(4), b = 8.954(3), c = 16.805(6) Å, and β = 107.5(1)°. The structure was refined by least squares techniques to a final discrepancy factor of 0.041 based on 2234 observed independent reflexions.
The compound is polymeric with copper atoms alternately bridged by two oxygen atoms and two thiocyanato groups. The coordination geometry around each copper atom is distorted square pyramidal. The basal plane consists of the two bridging oxygen atoms (mean value Cu-O: 1.914(3) Å), the amino nitrogen atom (mean value Cu-N: 2.035(3) Å) and the nitrogen atom from the thiocyanato group (mean value Cu-N: 1.908(3) Å) while the axial coordination site is occupied by a sulfur atom from a thiocyanato group (mean value Cu-S: 2.979(2) Å) centrosymmetric to the first.
The magnetic susceptibility of the compound shows a broad maximum at 200 K
Zur Beziehung von Struktur und Reaktivität cyclischer CH-acider Verbindungen bei der Kondensation mit Orthoameisensäuretriäthylester.
Authors: Wolfbeis Otto S. , Junek H. 
Published: March 2015

Condensation of triethylorthoformate with cyclic methylene-active compounds gives rise to ethoxymethylene-, bismethenyl- or triscompounds of type A, B or C resp. An explanation of this different behavior can be obtained by comparing the π-electron densities at the β-carbon atom of the exocyclic double blond of ethoxymethylen- and bismethenyl-compounds, which are calculated using HMO-theory. These calculationes show a limiting electron density, which can be used to explain the lack of further reaction to bis- and triscompounds, when certain heterocyclic active methylenes are used.
Reactions of some heterocyclic diketones have been studied and, their behavior found in agreement with theoretical concepts
Crystal Structures of the High Pressure Phases ZnAs and CdAs
Authors: Clark J. B. , Range Klaus-Jügen 
Published: March 2015

The structure of the high pressure compounds ZnAs and CdAs have been determined using Guinier film and counter methods. The compounds are orthorhombic, (space group Pbca; Z = 8), with α = 5.679(2) Å, b = 7.277(4) Å, c = 7.559(4) Å and α = 5.993(4) Å, b = 7.819(6) Å, c = 8.011(6) Å respectively.
ZnAs and CdAs are isostructural with the normal pressure phases ZnSb and CdSb, which are related to the high pressure phase Si III. Structural relationships are discussed including the Si III-diamond structure relationship.
Photoionization of Indole in Alkaline Aqueous Solutions at 77°K
Authors: Yamashita Shozi , Yoshida Mizuki , Tomita Giiti 
Published: March 2015

The photoionization process of indole in alkaline aqueous solutions at 77°K and the recombination process of trapped electron with its mother molecule were investigated. The fluorescence spectrum of indole in these glassy media depended on the NaOH concentration; the disappearance of the 325 nm band at the NaOH concentrations higher than 5 M with the appearance of a fluorescence band at 375 nm. The latter emission is possibly ascribed to the fluorescence of indole anion formed by proton dissociation in the excited singlet state of indole. The intensities of the 375 nm band and the ESR signal due to trapped electrons were dependent on the NaOH concentration and increased steeply with increasing the NaOH concentration. There was a parallel relation between the indole anion concentration and the trapped electron density to some extent.
The dependence of the ESR signal intensity on irradiation intensity suggested that the photoionization of indole in alkaline aqueous solution occurred through a two photon process. The presence of a photoactive intermediate for absorbing the second photon was further investigated with simultaneous irradiation of two different wavelength lights.
The trapped electron was detrapped with the irradiation of visible light (e.g. 580 nm), and its recombination with mother molecule caused an emission with the same spectrum as indole phosphorescence. The molecular species of the photoactive intermediate in alkaline aqueous solutions seems to be the indole anion. The photoionization in NaOH aqueous solution at 77°K was also compared with that in methanolic glassy solution.
Some New Tetrahydrothiopyrano [2,3-d] thiazole-2-thione Derivatives and their Biological Activities
Authors: Kassab Nazmi Abd Elatife , Abdallah Sanaa Osman , Ead Hamed Abdel Reheem , Zaki Doreya 
Published: March 2015

The arylidene derivatives (1) of 3-phenyl-1,3-thiazolidine-2,4-dithione undergo 1,4-cycloaddition reaction with acrylonitrile, ethyl acrylate, ω-nitrostyrene, styrylethyl ketone and N-arylmaleimides leading to substituted tetrahydrothiopyrano-7 H[2,3-d]thiazole-2-thiones (2) and (3).
The bactericidal and fungicidal activities of the new products were tested.
Notizen: Die Kristallstruktur einer neuen Modifikation des Kaliumamids, KNH2.
Authors: Jacobs H. , Von Osten E. 
Published: March 2015

In the temperature range from 54 to 75°Ca new modification of KNH2 was found, which crystallizes tetragonally a = 4.282 ± 0.003 Å, c = 6.182 ± 0.003 Å, and c/a = 1.444 (60°C), in P4/nmm - No. 129-, Z = 2,
2 K in 2c 0 1/2 z, z = 0.202(5),
2 N in 2c 0 1/2 z, z = 0.737(15). Its structure is of a deformed sodium chloride type.
The Reactions of Halogenocyclophosphazenes with Nitrogenous Bases
Authors: Shaw Robert A. 
Published: March 2015

The reactions of hexachlorocyclotriphosphazatriene, N3P3Cl6, and to a lesser extent octachlorocyclotetraphosphazatetraene, N4P4Cl8, and other halogenocyclophosphazenes with primary, secondary, and tertiary amines, are described. The effect on the substitution pattern of variables such as the structure of the amine, nature of the reaction solvent, etc., are discussed in some detail. Attention is drawn to the importance of steric effects. Isomerisation reactions are referred to.
The physical properties of aminocyclophosphazenes and aminohalogenocyclophosphazenes are discussed in some detail. These include basicity studies, 1H and 31P NMR and 35Cl NQR studies, Faraday effect measurements, etc. Attempts are made to correlate the above properties with X-ray crystallographic studies and quantum chemical calculations. The distinction between ground state and perturbed state properties is emphasised.
Synthesis, structure, and properties of phosphazenylcyclophosphazenes and related compounds are described and a novel conformational behaviour is discussed and rationalised.
Pyrimidine Derivatives and Related Compounds, III / Synthesis of Some New Pyrazolo [1,5-a] pyrimidines and Pyrazolo [3,4-d] pyrimidine Derivatives
Authors: Elnagdi Mohamed Hilmy , Fahmy Sherief Mahmoud , Zayed Ezzat Mohamed , Ilias Mohamed Ajmal Mohamed 
Published: March 2015

Whereas β-cyanoethylhydrazine (1) reacts with the β-ethoxy-α,β-unsaturated nitriles (2a—c) to yield the 5-amino-1-B-cyanoethylpyrazoles (8a—c), 1 reacts with anilinomethylenemalononitrile (2d) to yield 3-amino-1-B-cyanoethyl-4-cyanopyrazole (4; R=H; X=CN). 3a readily cyclised into the 5-amino-6,7-dihydropyrazolo[1,5-a]pyrimidine derivative (6) by the action of ethanolic guanidine. 6 was readily converted into the oxo derivative (7) by the action of acetic acid. 7 was also obtained by the action of 1% NaOH on 3a. On the other hand, 3b afforded a mixture of the pyrazolo[1,5-a]pyrimidine derivative (8) and the carboxylic acid (9) when treated with 1% NaOH solution.
3-Aminocrotononitrile (2e) reacted with 1 to yield the hydrazone derivative (12). The latter derivative was converted into the pyrazolo[1,5-a]pyrimidine derivative (14) by the action of acetic acid. On the other hand, the hydrochloride (15) was formed on treatment of 12 with acetic acid hydrochloric acid mixture.
Compounds 8 a, b reacted with carbon disulphide to yield the pyrazolo[3,4-d]-6 (7 H)-m- thiazinethione derivatives (16a,b). The latter were readily converted into the pyrazolo-[3,4-d]pyrimidine derivatives (17 a, b) by the action of aqueous NaOH solution.
Notizen: Oberflächenverbindungen von Übergangsmetallen, XVII / Surface Compounds of Transition Metals, XVII / Sauerstoffempfindlichkeit koordinativ ungesättigter Oberflächenverbindungen / Oxygen Sensitivity of Coordinatively Unsaturated Surface Compounds
Authors: Moeseler R. , Horvath B. , Lindenau D. , Horvath E. G. , Krauss H. L. 
Published: March 2015

The oxygen partial pressure above supported, coordinatively unsaturated CrII, VIII, MoII and MnII species was measured with a ZrO2 cell. Within this series the pressure ranges from 10-6 to 10-11 ppm O2, with the MnII/SiO2 systems exhibiting the lowest values of 10-10.8 and 10-11.3. Other pertinent properties like chemiluminescence with O2 and catalytic activity in ethylene polymerisation are also indicated.
The manganese(II) absorption masses are thus particularly suitable for removal of traces of oxygen from liquids and gases in general but especially from polymerizable olefins.
Die Kristall- und Molekülstrukturen von Dichlor(methylthio)boran und Dibrom(methylthio)boran.
Authors: Pollitz Stefan , Zettler Frowin , Forst Detlev , Hess Heinz 
Published: March 2015

The crystal structures of the title compounds were determined. Both compounds are isostructural and do not exist as dimers as previously assumed but as trimers in the form of six-membered rings in the chair conformation.
Mean values of the bond distances are B-Cl 1.80 A, B-Br 1.96 A, B-S 1.95 A, S-C 1.84 A.
Defined Intercalation Stages from Cathodic Reduction of MoS2 in Organic Electrolytes
Authors: Besenhard J. O. , Meyer H. , Schöllhorn R. 
Published: March 2015

Cathodic reduction of MoS2 in DMSO electrolytes containing alkali cations A+ results in the formation of defined ternary phases A+0.125 (DMSO)y[MoS2]0.125- with highly mobile solvated interlayer cations. Reduction of MoS2 in DME electrolytes yields similar products.
Basal spacings are dependant on solvent type and on ionic radius of A+. Further reduction of these compounds is associated with irreversible processes.
Notizen: Synthesis and Structural Investigation of an Unusual Double Hydrogen-Bridged Dimeric Cyclophosphazene Derivative
Authors: Bullen Graham J. , Dann Peter E. , Evans Moyra L. , Hursthouse Michael B. , Shaw Robert A. , Wait Keith , Woods Michael , Yu Hon Sum 
Published: March 2015

The formation, 1H NMR spectroscopic and X-ray crystallographic investigations of a double hydrogen-bridged tricyclic system of a cyclotriphosphazadiene derivative,
[N3HP3(O)Cl2(NEt2)3]2

are described and discussed. This is the first neutral molecule having both cyclophosphazene and cyclophosphazane character to be structurally investigated.
Silbersalzreaktionen eines Thiatriazinrings.
Authors: Roesky Herbert W. , Zamankhan Hamid 
Published: March 2015

1 reacts with SCl2 to yield 2. The methylsilane derivatives
[OC–NCH3–CO–NCH3-SO2–N]nSi(CH3)4-n

for n = 2, 3 and 4 are readily prepared from 1 and (CH3)2SiCl2, CH3SiCl3 and SiCl4. The IR and mass spectra are reported.
Reactions of Benzofurans, V Formylation and Bromination of 2,3-Diphenylbenzofuran
Authors: Hishmat O. H. , Abd-El-Rahman A. H. 
Published: March 2015

VILSMEIER-HAACK: formylation of 2,3-diphenylbenzofuran (la) gave the 5,6-diformyl derivative (lb). Huang-Minlon reduction of lb yielded the 5,6-dimethyl derivative (1c). Oxidation of 1c followed by hydrolysis the 2-hydroxy-4,5-dimethylbenzophenone (2b) was obtained.
Condensation of lb with primary amines gave the corresponding Schiff bases (3 a-j).
1a on bromination gave 5-bromo-2,3-diphenylbenzofuran (1 d), which on hydrolysis via oxidation yielded 2-hydroxy-5-bromobenzophenone (2 d). 1d was also obtained by condensation of benzoin and p-bromophenol in presence of sulphuric acid.
Conrad-Limpach reaction of 5-methoxy-6-amino-2,3-diphenylbenzofuran (1e) and ethyl acetoacetate gave 2,3-diphenyl-7-methyl-5-methoxy-9-hydroxy[2,3-f]furoquinoline via the azomethine (4).
Zur Darstellung und Kristallstruktur von Na2CuAs, K2CuAs und K2CuSb.
Authors: Eisenmann Brigitte , Savelsberg Gerhard , Schäfer Herbert 
Published: March 2015

The three new compounds crystallize orthorhombic, space group Cmcm with
Na2CuAs: a = 8.86(2) Å, b = 7.22(2) Å, c = 5.34(2) Å;
K2CuAs: a = 10.02(2) Å, b = 7.56(2) Å, c = 5.89(2) Å;
K2CuSb: a = 10.50(2) Å, b = 7.93(2) Å, c = 6.23(2) Å.
There are Cu–E(V)–Cu–E(V)-zigzag-chains in the structure, in which the Cu-atoms are linearly bonded to the E(V)-atoms.
Aluminium-Stickstoff-Verbindungen mit adamantanähnlichem Gerüst. / Aluminium Nitrogen Compounds Having a Skeleton Similar to Adamantane
Authors: Nöth H. , Wolfgardt P. 
Published: March 2015

Aluminium nitrogen compounds having an adamantane cage structure 1 are produced from aminoalanes HXAlN(CH3)2 (X = H, Cl, Br, I) and primary amines. The hydridic Η-atoms of [(R2NAlH)2NR]2 (R = CH3) can be replaced by halogen using mercury halides. In contrast, methylation was not achieved by Hg(CH3)2 or Al(CH3)3 · O(C2H5)2 respectively. LiAlH4 and (CH3)2NH degrade the adamantane skeleton with aminoalane formation.
The spectroscopic data of the new compounds will be discussed
Beiträge zur Untersuchung anorganischer nichtstöchiometrischer Verbindungen, VI: Präparative und strukturelle Untersuchung von WNb15O40F und nahe benachbarten Defektstrukturen im System Nb2O5—WO3—NbO2F / Contributions to the Study of Inorganic Non-Stoichiometric Compounds, VI: Preparative and Structural Investigations of WNb15O40F and Closely Related Defect Structures in the System Nb2O5—WO3—NbO2F
Authors: Krämer Eberhard , Gruehn Reginald 
Published: March 2015

In the quaternary system H–Nb2O5–WO3–NbO2F the phase WNb15O40F was prepared in form of light-yellow needles. The compound crystallizes in the monoclinic system with the unit cell dimensions a = 22.254 A, b = 3.829 A, c = 20.298 A and β = 114.29°, space group C 2. Electron optical investigations showed the crystal structure containing 5 x 3 x co-blocks of Nb—(O, F)-octahedra, with metal atoms in tetrahedral positions located at the junctions of every four blocks. X-ray investigations showed a range of homogeneity between (O, F)/ (W, Nb) = 2.556 &lt; 2.563 (WNb15O40F) &lt; 2.571.
The hypothetical phase WNb18O47F2 with 6 x 3-blocks was found as a microdomain by electron microscopy.
Cu2+-Ionen in tetragonal gestauchten Koordinationsoktaedern — Spektroskopische Untersuchungen zum Jahn-Teller-Effekt von Cu2+ in Mischkristallen Ba2CuxZn1-xF6.
Authors: Friebel C. , Propach V. , Reinen D. 
Published: March 2015

Usually the Jahn-Teller effect of Cu2+ in a regular octahedral host lattice site leads to a tetragonal elongation with a small o-rhombic component. If the relevant crystallographic site is slightly tetragonally compressed however in the host lattice structure already – as in Ba2ZnF6 – the Jahn-Teller effect may stabilize this distortion symmetry as well. This can be deduced from the EPR-spectroscopic gn -values of 1.99 for the mixed crystals Ba2Zn1-xCuxF6 up to x = 0.3. The angular overlap parameters obtained from the ligand field spectra suggest in addition, that the tetragonal compression of the CuF6 polyhedra is considerable, with CuF distances of about 1.90 Å (2 x) and 2.14 Å (4 x), respectively.
Increasing cooperative elastic interactions between the CuF6 polyhedra in the (001) planes at larger Cu2+-concentrations induce tetragonally elongated octahedra (with a small o-rhombic component) in antiferrodistortive order at x ≥ 0.6. This cooperative Jahn-Teller order, which is characteristic for Ba2CuF6, can be verified simply by acentric displacements of the F-.ligands connecting two Cu2+-ions in the (001) planes.
Darstellung und spektroskopische Untersuchung von Bis(alkylmetall)-diacetylhydrazinderivaten des Aluminiums, Galliums, Indiums und Antimons / Preparation and Spectroscopic Investigations on Bis(alkylmetal)diacetylhydrazin Derivatives of Aluminium, Gallium, Indium and Antimony
Authors: Eberwein Bernd , Lieb Waldemar , Weidlein Johann 
Published: March 2015

The interaction of N,N′-diacetylhydrazine with the trialkys of aluminium, gallium and indium and with Sb(CH3)5 yields bis(alkylmetal) compounds of the formula (RxM)2[O2N2(CCH3)2]
(x = 2, M = Al, Ga, In; R = CH3, C2H5 and x = 4, M = Sb; R = CH3). The M2O2N2C2 skeleton of these compounds forms a centrosymmetric system of two fused five-membered rings, with C2h or S2 symmetry.