- Structural characterization of methanol substituted lanthanum halides
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The first study into the alcohol solvation of lanthanum halide [LaX3] derivatives as a means to lower the processing temperature for the production of the LaBr3 scintillators was undertaken using methanol (MeOH). Initially the de-hydration of {[La(μ-Br)(H2O)7](Br)2}2 (1) was investigated through the simple room temperature dissolution of 1 in MeOH. The mixed solvate monomeric [La(H2O)7(MeOH)2](Br)3 (2) compound was isolated where the La metal center retains its original 9-coordination through the binding of two additional MeOH solvents but necessitates the transfer of the innersphere Br to the outersphere. In an attempt to in situ dry the reaction mixture of 1 in MeOH over CaH2, crystals of [Ca(MeOH)6](Br)2 (3) were isolated. Compound 1 dissolved in MeOH at reflux temperatures led to the isolation of an unusual arrangement identified as the salt derivative {[LaBr2.75·5.25(MeOH)]+0.25 [LaBr3.25·4.75(MeOH)]-0.25} (4). The fully substituted species was ultimately isolated through the dissolution of dried LaBr3 in MeOH forming the 8-coordinated [LaBr3(MeOH)5] (5) complex. It was determined that the concentration of the crystallization solution directed the structure isolated (4 concentrated; 5 dilute) The other LaX3 derivatives were isolated as [(MeOH)4(Cl)2La(μ-Cl)]2 (6) and [La(MeOH)9](I)3·MeOH (7). Beryllium Dome XRD analysis indicated that the bulk material for 5 appear to have multiple solvated species, 6 is consistent with the single crystal, and 7 was too broad to elucidate structural aspects. Multinuclear NMR (139La) indicated that these compounds do not retain their structure in MeOD. TGA/DTA data revealed that the de-solvation temperatures of the MeOH derivatives 4-6 were slightly higher in comparison to their hydrated counterparts.
- Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
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p. 1784 - 1795
(2010/07/03)
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- On the reactivity of lanthanide iodides LnIx (x < 3) formed in the reactions of lanthanide metals with iodine
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The reduced lanthanide iodides of the composition LnIx (Ln = Sc, Y, La, Ce, Pr, Gd, Ho, and Er; x 3) were obtained by the reaction of an excess of the appropriate metal with iodine at high temperatures. The diamagnetism of the Sc, Y, and La d
- Khoroshenkov,Petrovskaya,Fedushkin,Bochkarev
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p. 699 - 702
(2008/10/08)
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- Rare earth iodide complexes of 4-formyl-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one
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Rare earth complexes of 4-formyl-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (FDPP) having the general formula [Ln(FDPP)4I2]I, where Ln = Y, La, Pr, Nd, Sm, Eu, Gd, Dy, Ho and Er, have been synthesised and characterised by elemental analyses, molar conductance in non-aqueous solvents, electronic, infrared and proton NMR spectra as well as thermogravimetric analyses. FDPP acts as a neutral monodentate ligand coordinating through the ring carbonyl oxygen. Two of the iodide ions are coordinated. A coordination number of six may be assigned to the metal ion in these complexes. The covalency parameters evaluated from the solid state electronic spectra suggest weak covalent character of the metal-ligand bond. The TG data of the lanthanum complex indicate that the complex is stable up to about 140° C and undergoes decomposition in three stages forming lanthanum oxide as the final product.
- Joseph, Siby,Radhakrishnan
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p. 1219 - 1229
(2008/10/09)
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- Thermal Constants of Melting of Holmium Iodide
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HoI3 was synthesized by iodination of holmium metal by iodine vapor. The product was identified by chemical and X-ray diffraction analyses. The melting point (Tm(HoI3) = 1226 ±2 K) and enthalpy of melting (ΔmH°(HoI3) = 23 ±3 kJ/mol) were determined by DTA. The entropy of melting δmS°(HoI3) was calculated to be 18 ± 4 J/(mol K).
- Goryushkin,Poshevneva,Vinokurova
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p. 1467 - 1468
(2008/10/08)
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