Chromium magnetic moment

It is clear that an ah initio calculation of the ground state of AF Cr, based on actual experimental data on the magnetic structure, would be at the moment absolutely unfeasible. That is why most calculations are performed for a vector Q = 2ir/a (1,0,0). In this case Cr has a CsCl unit cell. The local magnetic moments at different atoms are equal in magnitude but opposite in direction. Such an approach is used, in particular, in papers [2, 3, 4], in which the electronic structure of Cr is calculated within the framework of spin density functional theory. Our paper [6] is devoted to the study of the influence of relativistic effects on the electronic structure of chromium. The results of calculations demonstrate that the relativistic effects completely change the structure of the Or electron spectrum, which leads to its anisotropy for the directions being identical in the non-relativistic approach. 

Tris(bipyridine)ehromium(II) perchlorate is stable for long periods in dry air but slowly oxidizes when wet. It has a room-temperature magnetic moment of 3.0 B.M., typical of a low-spin chromium(II) compound.18... 

Complexes of adenine (10 Ade) have been isolated by mixing the ligand in 2-methoxy-ethanol with chromium(II) halides in butanol. The low magnetic moments (Table 16)104 indicate dinuclear species [Cr2X2(Ade)4+] (Section 35.3.5.5), or polynuclear structures with bidentate adenine. 

Diarsine forms the low-spin, tram octahedral chromium(ll) complexes [CrX2(diars)2] (X = Cl, Br, I) the magnetic moments are in the range 2.85 to 2.99 BM and independent of temperature (84-298 K). Reflectance spectra have been recorded, but no assignments made.40... 

Complexes of acetylacetone (acacH), benzoylacetone (bzacH) and dipivaloylmethane (dpmH) have been reported. The acetylacetonate [Cr(acac)2] has been prepared from chromium(II) acetate and acetylacetone.142,143 It can also be obtained by the addition of aqueous sodium acetylacetonate to an aqueous solution of chromium(II) chloride, but in any preparation the yellow solid must be filtered off and dried as rapidly as possible, otherwise the chromium(III) compound is obtained. Its magnetic moment is 4.99 BM at room temperature consistent with a high-spin d4 configuration. 142The powerful reducing ability of [Cr(acac)2] has been used to prepare iron(II) and chromium(II) complexes80 of porphyrins and related ligands. 

Chromium(II) chelates of 3-(N-2-furfuralideneimino)propionic acid (HFP), o-(JV-ar-furfurali-dene)benzoic acid (HFB), and o-(N-ar-furfuralideneimino)ethanesulfonic add (HFE)284-286 have been found to have magnetic moments of approximately 4.8 BM at room temperature. A band near 14500 cm-1 (CHC13 solution) has been assigned to the % 5T transition and formation constants have been measured. However, there is no indication of difficulties arising from the air sensitivity of chromium(II) solutions. 

Table 75 Electronic Spectra and Magnetic Moments of Chromium(III) Biguanide Complexes...

These methods, particularly (2), have been used in the preparation1316 of other chromium(IV) tertiary alkoxides (Table 108). These are blue liquids or low melting solids which can be distilled in vacuum and are monomeric in cyclohexane. Their magnetic moments are close to 2.8 BM and that of Cr(OBu )4 is almost independent of temperature as expected for tetrahedral Cr1 " (d2, pm — 2.83 BM). The electronic absorption spectrum of blue Cr(OBu )4... 

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