Spektroskopische Untersuchungen zum Jahn-Teller-Effekt des Cu2+-Ions in Verbindungen vom Typ A2 CuL6, I / Spectroscopic Ivestigations with Respect to the Jahn-Teller-Effect of Cu(II) in Compounds of the Type A2CuL6, I

1974 ◽  
Vol 29 (5-6) ◽  
pp. 295-303 ◽  
Author(s):  
Claus Friebel
Keyword(s):  
Esr Spectra ◽  
Ligand Field ◽  
X Ray ◽  
Octahedral Sites ◽  
Structural Differences ◽  
Structure Determinations ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Ligand Field Spectra ◽  
Atomic Parameters

Structural relations between perovskite-related lattices of the type A2CuL6 and the perovskite compounds A2(12) [BCu](6)L6 (1: 1 order in the octahedral sites, elpasolite type) are demonstrated by two examples, the compounds A,Cu(OH)6 [A = Ba, Sr] and Ba2CuF6. From the ESR spectra a coupling of Jahn-Teller-distorted Cu-ligand-octahedra in these compounds corresponding to a “disturbed” type of antiferrodistortive order can be deduced. This result is in agreement with recent X-ray structure determinations. The ligand field spectra of the hydroxocuprates(II) indicate tetragonally elongated CuO6-octahedra with very long axial distances. From the ESR investigations further conclusions can be drawn concerning structural differences between the Ba- and the Sr-compound [Sr2Cu(OH6)], the atomic parameters of which are still unknown.

Syntheses and Structures of Manganese(II) and Manganese(III) Nitrate Diaminosarcophagine Complexes

1993 ◽  
Vol 46 (4) ◽  
pp. 465 ◽  
Author(s):  
II Creaser ◽  
LM Engelhardt ◽  
JM Harrowfield ◽  
AM Sargeson ◽  
BW Skelton ◽  
...  
Keyword(s):  
Transition Metals ◽  
Single Crystal ◽  
X Ray ◽  
Manganese Ion ◽  
Structure Determinations ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
The Mean ◽  
Appreciable Variation ◽  
Amine Ligand

The syntheses of [ Mn ((NH3)2sar)](NO3)4.H2O and [ Mn ((NH3)2sar)](NO3)5.2H2O, manganese(II) and manganese(III) complexes of the cage amine ligand diaminosarcophagine ( di-aminosarcophagine = (NH2)2sar = 1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6] icosane ) in its diprotonated form are recorded, together with their single-crystal X-ray structure determinations at c. 295 K. The monoclinic P21 array of the manganese(II) complex (a 12.386(5), b 12.431(4), c 8.598(4) Ǻ, β 93.89(4)°, V 1321(1) Ǻ3,Z 2) is archetypical for similar complexes of a wide variety of transition metals; for the present determination, R was 0.027 for 2013 'observed' (I > 3σ(I)) reflections. The manganese(III) complex is monoclinic C 2/c, a 10.744(2), b 13.294(4), c 20.462(9) Ǻ, β 102.38(3)°, Z 4; R was 0.055 for 1629 'observed' reflections. Both structures show the six secondary nitrogen atoms of the ligand to be bound to the manganese ion in a configuration approximately halfway between a trigonal prism and an octahedron. The ligand is in the lel3 conformation. In the first complex, Mn -N distances, appropriate to high-spin manganese(II), range from 2.228(3) to 2.253(3) Ǻ, mean 2.238 Ǻ; in the second, surprisingly, the distances are even more closely ranged (unlike those of the sarcophagine analogue of the previous paper), 2.115(4)-2.127(4) Ǻ, the mean (2.122 Ǻ) being closely comparable to that recorded for the sar analogue, and show no appreciable variation attributable to the expected Jahn-Teller effect.

scholarly journals ESR-Untersuchungen zum Jahn-Teller-Effekt des Cu2+-Ions in oxidischen Perowskiten

1969 ◽  
Vol 24 (10) ◽  
pp. 1518-1525
Author(s):  
C. Friebel ◽  
D. Reinen
Keyword(s):  
Phase Transition ◽  
Tetragonal Phase ◽  
Esr Spectra ◽  
Ligand Field ◽  
X Ray ◽  
Field Spectroscopy ◽  
Jahn Teller ◽  
Low X ◽  
Ligand Field Parameters ◽  
Tetragonal Phase Transition

Abstract The ESR-powder-spectra of the perovskite-mixed-crystals M2II (CuxZn1-xW)O6 [MII=Sr, Ba] and Sr2(CuxZn1-xTe)O6 , which have been investigated by means of conventional X-ray-techniques and ligand-field-spectroscopy 1,2, are described and the results extensively discussed. The conclusions can be summarized as follows: (a) At very low x-values isolated, dynamically Jahn-Teller-distorted CuO6-octahedra are present in the cubic matrices, which can be frozen into tetragonally elongated polyhedra at 4.2 °K; (b) At high x-values the CuO6-entities are statically JT-distorted with the long axes lined up along the c-axis of the macroscopically tetragonal phases; (c) The ESR-spectra around the cubic-tetragonal phase-transition are complex, containing signals of obviously magnetically coupled Cu2+-ions; (d) The g-values "follow" the ligand-field-parameters quantitatively. Comparative data of some other compounds are given.

Spektroskopische Untersuchungen zum Jahn-Teller-Effekt des Cu2+-Ions in Verbindungen vom Typ A2CuL6, II / Spectroscopic Investigations with Respect to the Jahn-Teller Effect of Cu(II) in Compounds of the Type A2CuL6, II

1974 ◽  
Vol 29 (9-10) ◽  
pp. 634-641 ◽  
Author(s):  
Claus Friebel
Keyword(s):  
Structure Determination ◽  
Qualitative Agreement ◽  
Spectroscopic Data ◽  
Ligand Field ◽  
Orthorhombic Distortion ◽  
X Ray ◽  
Bond Lengths ◽  
Field Spectroscopy ◽  
Jahn Teller ◽  
Jahn Teller Effect

By means of EPR and ligand field spectroscopy a refinement of the Ba2CuF6 structure within the [CuF4/2F2]2--layers consisting of axially elongated CuF6-octahedra, 2-dimensionally connected by corners in an antiferrodistortive order, is given. In qualitative agreement with a recent structure determination by X-ray analysis the spectroscopic data prove, that the equatorial planes of the coupled CuF6-polyhedra form an angle of 2 γ > 90° (corresponding to a disturbed type of antiferrodistortive order). In contrast to 2 γ= 101° found by the X-ray investigation, the spectroscopic results suggest 2 γ = 119 (± 1)°, the consequence of which is an elongation of the Cu—F bond lengths and a remarkable orthorhombic distortion of the CuF6-octahedra.

scholarly journals Cu2+-Ionen in tetragonal gestauchten Koordinationsoktaedern — Spektroskopische Untersuchungen zum Jahn-Teller-Effekt von Cu2+ in Mischkristallen Ba2CuxZn1-xF6.

1976 ◽  
Vol 31 (12) ◽  
pp. 1574-1584 ◽  
Author(s):  
C. Friebel ◽  
V. Propach ◽  
D. Reinen
Keyword(s):  
Lattice Site ◽  
Lattice Structure ◽  
Host Lattice ◽  
Teller Effect ◽  
Ligand Field ◽  
Crystallographic Site ◽  
Elastic Interactions ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Ligand Field Spectra

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.

The Coordination Chemistry of Phosphoryl Compounds Containing the — N(CH3)2 Group, Part VIII

1972 ◽  
Vol 27 (7) ◽  
pp. 759-763 ◽  
Author(s):  
M. W. G. De Bolster ◽  
W. L. Groeneveld
Keyword(s):  
Coordination Chemistry ◽  
General Formula ◽  
Ligand Field ◽  
Chemical Analyses ◽  
X Ray ◽  
Physical Measurements ◽  
Ligand Field Spectra ◽  
Chloride Adduct ◽  
Ligand Field Parameters ◽  
Group Part

A number of new solvates and adducts containing bisphenyldimethylaminophosphine oxide is reported. The solvates have the general formula M[(C6H5)2P(O)N(CH3)2]42+(anion-)2, in which M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd, and the anions are ClO4- and BF4-. The adducts have the general formula M[(C6H5)2P(O)N(CH3)2]2Cl2, where M stands for the same series of metals.The compounds are characterized and identified by chemical analyses and physical measurements.Ligand-field and vibrational spectra have been investigated; values for the ligand-field parameters are reported. It is concluded that coordination takes place via the oxygen atom of the ligand.X-ray powder patterns were used in combination with ligand-field spectra to deduce the coordination around the metal ions.The interesting behaviour of the nickel (II) chloride adduct upon heating is discussed and it is shown that both a square pyramidal and a tetrahedral modification exists.

scholarly journals The crystal structure of szenicsite, Cu3MoO4(OH)4

1998 ◽  
Vol 62 (04) ◽  
pp. 461-469 ◽  
Author(s):  
Peter C. Burns
Keyword(s):  
Crystal Structure ◽  
Goodness Of Fit ◽  
Direct Methods ◽  
Ligand Field ◽  
Area Detector ◽  
Vertex Sharing ◽  
Distorted Octahedral ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Least Squares Techniques

Abstract The crystal structure of szenicsite, Cu3MoO4(OH)4, orthorhombic, a = 8.5201(8), b = 12.545(1), c = 6.0794(6) Å, V = 649.8(2) Å3, space group Pnnm, Z = 4, has been solved by direct methods and refined by least-squares techniques to an agreement index (R) of 3.34% and a goodness-of-fit (S) of 1.11 for 686 unique observed [|F| ⩾ 4σF] reflections collected using graphite-monochromated Mo-Kα X-radiation and a CCD area detector. The structure contains three unique Cu2+ positions that are each coordinated by six anions in distorted octahedral arrangements; the distortions of the octahedra are due to the Jahn-Teller effect associated with a d 9 metal in an octahedral ligand-field. The single unique Mo6+ position is tetrahedrally coordinated by four O2− anions. The Cu2+ϕ6 (ϕ: unspecified ligand) octahedra share trans edges to form rutile-like chains, three of which join by the sharing of octahedral edges to form triple chains that are parallel to [001]. The MoO4 tetrahedra are linked to either side of the triple chain of Cu2+ϕ6 octahedra by the sharing of two vertices per tetrahedron, and the resulting chains are cross-linked through tetrahedral-octahedral vertex sharing to form a framework structure. The structure of szenicsite is closely related to that of antlerite, Cu3SO4(OH)4, which contains similar triple chains of edge-sharing Cu2+ϕ6 octahedra.

Pyroxene-type compounds NaM3+Ge2O6, withM= Ga, Mn, Sc and In

2014 ◽  
Vol 70 (9) ◽  
pp. 852-857 ◽  
Author(s):  
Günther J. Redhammer ◽  
Gerold Tippelt
Keyword(s):  
Ambient Pressure ◽  
Tetrahedral Site ◽  
Exceptional Case ◽  
Temperature Structure ◽  
Present Sample ◽  
Teller Distortion ◽  
Octahedral Sites ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
The Individual

The four title compounds, namely sodium gallium germanate, NaGaGe2O6, sodium manganese vanadate germanate, NaMnV0.1Ge1.9O6, sodium scandium germanate, NaScGe2O6, and sodium indium germanate, NaInGe2O6, adopt the high-temperature structure of the pyroxene-type chain germanates, with monoclinic symmetry and space groupC2/c. The lattice parameters, the individual and average bond lengths involvingM1, and the distortion parameters scale well with the ionic radius of theM1 cation. NaGaGe2O6has more distortedM1 sites and more extended tetrahedral chains than NaInGe2O6, in which a high degree of kinking is required to maintain the connection between the octahedral and tetrahedral building units of the pyroxene structure. An exceptional case is NaMnGe2O6, in which the strong Jahn–Teller effect of Mn3+results in more distorted octahedral sites than expected according to linear extrapolation from the other NaM3+Ge2O6pyroxenes. In contrast with the literature, minor incorporations of V5+in the tetrahedral site and a corresponding reduction of Mn3+to Mn2+in the octahedral sites in the present sample lower the Jahn–Teller distortion and stabilize the Mn-bearing pyroxene, even allowing its synthesis at ambient pressure.

A Novel Method for Synthesizing Crystalline Copper Carbodiimide, CuNCN. Structure Determination by X-Ray Rietveld Refinement

2005 ◽  
Vol 60 (6) ◽  
pp. 593-596 ◽  
Author(s):  
Xiaohui Liu ◽  
Martial Aime Wankeu ◽  
Heiko Lueken ◽  
Richard Dronskowski
Keyword(s):  
Small Temperature ◽  
Interatomic Distances ◽  
X Ray ◽  
First Order ◽  
Metallic Conductor ◽  
Distorted Octahedral ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Novel Method ◽  
Aqueous Conditions

Well-crystallized copper carbodiimide, CuNCN, was synthesized by the slow oxidation of a copper(I) cyanamide precursor under aqueous conditions. The X-ray powder data evidence the orthorhombic system and space group Cmcm with a = 2.9921(1), b = 6.1782(1), c = 9.4003(2) Å , V = 173.769(5) Å3 and Z = 4. There is a strongly distorted octahedral Cu2+ coordination reflecting a typical first-order Jahn-Teller effect, with interatomic distances of 4×Cu-N = 2.001(2) Å and 2×Cu-N = 2.613(3) Å ; the NCN2− unit adopts the carbodiimide shape with C-N = 1.227(4) Å . Despite the formal d9 electron count of Cu2+, CuNCN exhibits a small temperature-independent paramagnetism and is likely to be a metallic conductor.

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