Antiferromagnetic properties

Oxovanadium(IV) complexes with SBs derived from Hsal or substituted Hsal and 2-amino-ethanethiol (83) and 3-aminothiophenol (84) were reported by Syamal756-758 and some properties are summarized in Table 40. The corresponding ligands with oxygen atoms instead of sulfur form tridentate complexes with antiferromagnetic properties (see Section 33.5.9.1.iv). 

The complexes of type 641 were obtained according to the same technique by interaction of ligands 640 with Co, Ni, Cu, Zn, and Cd acetates in methanol. In case of palladium acetate, acetone was used as solvent [95], The principal circumstance is the fact that, together with well-known and studied binuclear complexes 641 (X = Y = O) [92,93], a series of novel binuclear complexes (X = NTs, Y = 0, S) has been obtained and, in some cases, structurally characterized [94,96,98], They possess antiferromagnetic properties, which are especially characteristic for Cu, Ni, and Co complexes with M2S2bridge. Their magnetic moments at 78 K have considerably decreased magnitudes 1.45 B.M. (M = Co2+), 0.45 B.M. (M = Ni2+), and 0.41 B.M. (M = Cu2+) [95],... 

The 1-D antiferromagnetic properties of KCuF3, although unexpected at first sight from a crystallographic point of view, can nonetheless be easily explained on the basis of Jahn-Teller ordering (Sect. 3.1.1). 

Here we present a novel binuclear Ni(II) complex with imidazolate-bridged ligand. The two Ni(II) ions in the complex are pentacoordinated, and the geometry around each Ni(II) ion is a distorted square pyramid. The complex possesses weak antiferromagnetic property at low temperature. 

A carboxylate-bridged triironfll) complex of bis[(45)-(l-meth-ylethyl)oxazolin-2-yl]methane has also been prepared and its antiferromagnetic properties examined. ... 

First, practically nothing is said of the tremendous development in the so called HTCS, the new oxide superconductors. It could be argued that their metallic conductivity has been known much earlier than that of organic compounds. It is indeed a field by itself, which cannot possibly be dealt with here. It is, in a way, a great pity, as many similarities are observed, for instance between the oxide compounds and the organic charge transfer compounds, as stresses above normal , superconductive or antiferromagnetic properties, quasi low dimensionality, with exacerbated electron-electron interactions when localisation into Id is approached. .. 

The complexes 1-5 were prepared by stoichiometric milling in a Teflon beaker with agate balls for 30 min at 20 °C. All exhibited distinct melting points and distinct antiferromagnetic properties. 

The presence of the unpaired electrons implies some ferro- or/and antiferromagnetic properties of these materials, which indeed have been discovered in the HTS phenomenon. 

Most probably, the key phenomena take place in the copper-oxygen layers and may be described as a reversible reaction - - 0 C + -1- 0 or C + -1- 0 Cm" " -b 0 (a dot means an unpaired electron). The presence of the unpaired electrons implies some ferro- or/and antiferromagnetic properties of these materials, which indeed have been discovered in the HTS phenomenon. 

Magnetic properties of the Cei La Mn2Si2 system were investigated by the neutron diffraction and the magnetometry (Szytula and Siek 1982). The samples with low La concentration (x O.5) show antiferromagnetic properties. For... 

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