Hexachloro complexes

That magnetic measurements often raise more problems than they solve, is demonstrated for the indicated compound. We prepared a series of [ (C2H5N] i,An(NSC) e compounds (An = Th, U, Np, Pu) with cubic coordination of the actinide ion. We derived a consistent interpretation of the magnetic and optical properties of the uranium and the neptunium compounds (6 ). In the case of Pu we expect an isolated T1 ground state and a first excited state at about 728 cm-1. To our surprise we found a magnetic ground state much more pronounced than in the case of the hexachloro-complex, Fig. 4. 

This salt is a white crystalline solid made by treating polonium (IV) hydroxide or chloride with dilute acetic acid. Its solubility in the latter increased from 0.2 mg (of Po210)/liter in 0.1 N acid to 82.5 mg/liter in 2 N acid, indicating complex ion formation. The acetato complex is colorless in solution and appears to be more stable than the hexachloro complex (11). 

The reaction between MC35 and liquid N2Os resulted in the moisture sensitive tris(nitrato)oxo compounds [M0(N03)3].1 The (NMe4)[Nb0(N03)4] complexes were prepared by addition of liquid N2Os to the appropriate hexachloro complexes with covalently bonded... 

A few salts of composition (Et4N)2[MvOX5] (Mv = Pa, X = C1, Br MV = U, X = F) are known the uranium(V) compound is obtained from the dihydrate under vacuum, and the protactinium(V) chlorocompound is prepared by hydrolysis of the hexachloro complex salt in methyl cyanide containing 0.5% water. Salts of composition (Et4N)[Pa(OEt)2X4j (X = Cl, Br) are also known. 

The physical properties of the aqueous solutions were studied by Bucknall and coworkers 14 Ray and Bharls studied the magnetic susceptibility of the hexachloro complex. Potassium pentachloroaquomolybdate(III) exists as rhombic crystals and is isomorphous with potassium pentachloroaquoferrate(III).16 Potassium hexachloromo-lybdate(III) has been used for the preparation of potassium hexathiocyanatomolybdate(III), potassium heptacyano-aquomolybdate(III),17and potassium octacyanomolybdate-(IV).18... 

Also, in concentrated HC1, SbCls is present as a hexachloro complex as a result of the reaction... 

Cesium and ammonium hexachloro complexes precipitate when the component halides are reacted in thionyl chloride-iodine monochloride mixtures. 

A few derivatives of oxyanions have also been prepared protactinium (V) forms hexanitrato complexes, Pa(N03)e , by reaction of the hexachloro complex with dinitrogen pentoxide, in contrast to niobium and tantalum which, under similar conditions, yield only tetranitrato complexes, M0(N03)4 (35). Neptunium (V) nitrates, NPO2NO3 and Np0(N03)3 have also been reported 71). Protactinium (V) sulfato-and selenato complex acids, H3PaO( 804)3 and H3Pa0(Se04)3, have been obtained from aqueous solution (13), but no fully sulfated or sele-nated species have been recorded. 

This involves the use of tertiary amine extraction of the An ions from acidic 11 M LiCl solutions. Spectroscopic studies have indicated that, in the cases of Am and Nd at least, the octahedral trianionic hexachloro complexes are extracted from 11 M LiCl. Stability constant data for the chloride complexing of Am , and Cfin media of ionic strength 1,0 have been reported. Tertiary amines also extract Pu and a study of extraction from nitrate media by trilaurylamine (TLA) in xylene has been reported. " This showed that the mass transfer rate was controlled by the reactions between Pu from the bulk phase and interfacially adsorbed TLA-HNOs. The separation of individual transplutonium elements from the Tramex actinide product may be achieved using ion exchange or precipitation techniques." ... 

The temperature coefficient (at room temperature) of resonance frequencies of potassium hexachloro complexes increases progressively with decreasing atomic number of the central metal atom, i.e., with increasing electron deficiency of the central metal ions from Pt(IV) to W(IV) (-1,0,... 

From magnetic susceptibility measurements [69] and EPR measurements [70] of hexachloro complexes of Np", the ground state of the 19/2 term is shown to be a rg(Oh). Limits on the ratios of the fourth- to the sixth-order crystal field parameters have been determined, and these limits are consistent in the isostructural series MClg , M = Pa ", Np ". Depending on the cation... 

Fig. 4. Thermal stability of the hexachloro complex compounds of TiCh, ZrCh, and HfCh as a function of the radii of the alkali metal cations.

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