Search results for "SUSCEPTIBILITY"

Crystal Fields in Pr-Hydrides

1977

Inelastic neutron scattering was used to determine the crystal field splittings of PrD2 and PrD2.5. For the PrD2 crystal field at the Pr-site is cubic and can be explained by a negative charge of the hydrogen. The splitting observed for PrD2.5 can be described assuming a well defined short range order caused by a mer-configuration of the half filled octahedral hydrogen sites leading to an orthorhombic crystal field. The structure and the paramagnetic susceptibility of the Pr-hydrides are discussed on this basis.

[MnM(egta)]· 8H2O(M= Mn, Cd): A Novel Type of Two-Dimensional Magnetic Lattice

1993

Spin crossover in iron(II) tris(2-(2′-pyridyl)benzimidazole) complex monitored by variable temperature methods: synchrotron powder diffraction, DSC, …

2003

Abstract The thermal expansion of the spin crossover system [Fe(pybzim) 3 ](ClO 4 ) 2  · H 2 O (pybzim=2-(2 ′ -pyridyl)benzimidazole) has been determined from powder X-ray data between 50 and 250 K; the wavelength of the synchrotron source was 1.21888(1) A. The unit cell parameters of the triclinic crystal system were a =12.091 A, b =12.225 A, c =14.083 A, α =77.70°, β =80.35°, γ =74.35°, and V =1944.9 A 3 at 250 K. In addition to the linear thermal expansion of the unit cell volume, an extra expansion due to the low-spin (LS) to high-spin (HS) transition is observed. The V ( T ) function shows a sudden increase comparable with the step in the effective magnetic moment at the transition reg…

Structure and Magnetic Properties of the Ferromagnetic Cu3Cl126- Trimer in [(NH3C2H4)3NH]2Cu3Cl14

2004

The crystal structure consists of a strongly hydrogen bonded network of tris(N-ethylammonium)ammonium cations, Cu3Cl12(6)- trimeric species, and Cl- anions. The Cu3Cl12(6)- trimers are formed by two distorted tetrahedral CuCl4(2)- anions linked to a central square planar CuCl4(2)- anion via semicoordinate Cu-Cl...Cu mu1 bridges. The central copper ion shows only small deviations from ideal D4h symmetry, while the terminal copper ions show a mild distortion from D2d symmetry with an average trans Cl-Cu-Cl angle of 136.0 degrees. The semicoordinate linkages provide a ferromagnetic exchange pathway between the copper ions with J/k = 6.91(3) K. Short Cl...Cl contacts (3.67-3.90 angstoms) lead t…

Coexistence of spin-crossover and antiferromagnetic coupling phenomena in the novel dinuclear Fe(II) complex [Fe(dpa)(NCS)2]2bpym

2003

Abstract The iron(II) spin crossover dinuclear compound [Fe(dpa)(NCS) 2 ] 2 bpym where dpa = 2,2 ′ -dipyridylamine and bpym = 2,2 ′ -bipyrimidine has been synthesized and characterized. Variable-temperature magnetic susceptibility and 57 Fe Mossbauer spectroscopy data provide evidence for a rather complete and continuous S=2 ( HS )↔S=0 (LS) spin-crossover behavior taking place in the temperature range 400–50 K (T 1/2 =245 K ) without the presence of a plateau at 50% of conversion. The absence of such plateau, which is characteristic of all dinuclear compounds so far studied, is interpreted in terms of synergetic effect between intramolecular and intermolecular interactions.

Pressure-Induced Spin State Conversion in Antiferromagnetically Coupled Fe(II) Dinuclear Complexes

2001

The effect of pressure on the thermal dependence of the magnetic susceptibility has been investigated in the 2,2‘-bipyrimidine (bpm)-bridged iron(II) complexes of formula {[Fe(L)(NCX)2]2bpm} (X = S...

Polymorphism and Pressure Driven Thermal Spin Crossover Phenomenon in [Fe(abpt)2(NCX)2] (X=S, and Se): Synthesis,Structure and Magnetic Properties

2002

The monomeric compounds [Fe(abpt 2(NCX)2(X = S (1), Se (2) and abpt = 4-amino- 3,5-bis(pyridin-2-yl)-1,2,4-triazole) have been synthesized and characterized. They crystallize in the monoclinic P21/n space group with a = 11.637(2) A, b = 9.8021(14) A, c = 12.9838(12) A, β = 101.126(14)°, and Z=2 for 1, and a= 11.601(2) A, b = 9.6666(14) A, c = 12.883(2) A, β = 101.449(10)°, and Z = 2 for 2. The unit cell contains a pair mononuclear [Fe(abpt)2(NCX)21 units related by a center of symmetry. Each iron atom, located at a molecular inversion center, is in a distorted octahedral environment. Four of the six nitrogen atoms coordinated to the Fe(II) ion belong to the pyridine-N(1) and triazole-N(2) r…

ChemInform Abstract: Ferric Phosphite: Dimers of Face-Sharing Fe(III)O6 Octahedra. Crystal Structure Redetermination, Moessbauer Spectra, Magnetic Su…

2010

A 'Butterfly'-shaped Water Tetramer in a Cu4 Complex Supported by a Hydrazone Ligand: Synthesis, Crystal Structure, Magnetic Properties, and Quantum …

2009

A potentially tetradentate NOOO donor hydrazone ligand, LH2 (condensation product of benzhydrazide with O-vanillin) generates a tetranuclear CuII complex [Cu4(L)4]·4H2O (1), whose void spaces are occupied by water tetramers presenting a ‘butterfly’ conformation with the highest dihedral angle reported to date, as revealed by its X-ray crystal structure. 1 has also been characterized using various spectroscopic techniques, including IR, UV-vis, and elemental analysis. Variable temperature magnetic susceptibility measurements reveal the presence of moderate antiferromagnetic intra-tetramer coupling between the four CuII centres connected through simple oxo groups of the hydrazone ligand with…

Magnetization and61Ni Mössbauer effect study of the ternary arsenide CrNiAs

2008

The results of x-ray diffraction, dc magnetization, and 61Ni M?ssbauer spectroscopy studies of the ternary arsenide CrNiAs are reported. This compound crystallizes in the orthorhombic Fe2P-type structure (space group ) with the lattice parameters a = 6.1128(2)?? and c = 3.6585(1)??. CrNiAs is a mean-field ferromagnet with Curie temperature TC = 171.9(1)?K and the critical exponents ? = 0.514(18), ? = 1.010(16), and ? = 2.922(10). The temperature dependence of the magnetic susceptibility above TC follows the modified Curie?Weiss law with a paramagnetic Curie temperature of 176.0(3)?K and effective magnetic moment per transition metal atom of 2.42(1)??B. The magnetic moment per formula unit a…