13536-80-6Relevant articles and documents
Molecular and ionic sublimation of neodymium tribromide polycrystals and single crystals
Kudin,Butman,Motalov,Nakonechnyi,Kr?mer
, p. 1181 - 1188 (2009)
The molecular and ionic sublimation of polycrystals and single crystals under Knudsen effusion and Langmuir evaporation conditions is reported. In both sublimation regimes, the sublimation product at 780-1050 K contains neodymium tribromide monomer and dimer molecules, as well as the negative ions NdBr 4 -, Nd2Br 7 -, and Br-. The dimer-to-monomer flux ratio j(Nd2Br 6)/j(NdBr3)is larger in the molecular beam coming out of the effusion hole, while the ratio of the sublimation fluxes of the negative ions, j(Nd2Br 7 - )/j(NdBr 4 - ), is independent of the sublimation conditions. The partial pressures of the neutral components of the vapor have been determined, and the enthalpies and activation energies of sublimation of neodymium tribromide as monomer and dimer molecules and NdBr 4 - and Nd 2Br 7 - ions have been calculated. The equilibrium constants of ion-molecule reactions have been measured, and the enthalpies of these reactions have been determined. Based on these data, values of the thermodynamic properties Δ s H 0(298.15) and Δ f H 0(298.15) are recommended for the monomer and dimer molecules and the NdBr 4 - and Nd2Br 7 - ions.
Phase diagram and electrical conductivity of the AgBr-NdBr3 binary system
Kolodziej,Szymanska-Kolodziej,Chojnacka,Rycerz,Gaune-Escard
, p. 834 - 838 (2009)
DSC was used to investigate phase equilibrium in the AgBr-NdBr3 system. This binary mixture was characterized as an eutectic system with solid solutions. The eutectic composition and temperature were found to be: x(AgBr) = 0.845 and Teut/
Structural characterization of methanol substituted lanthanum halides
Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
, p. 1784 - 1795 (2010/07/03)
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.
Synthesis, structure and reactivity of tris-, bis- and mono(2,4- dimethylpentadienyl) complexes of neodymium, lanthanum and yttrium
Kunze, Michael R.,Steinborn, Dirk,Merzweiler, Kurt,Wagner, Christoph,Sieler, Joachim,Taube, Rudolf
, p. 1451 - 1463 (2008/10/09)
The tris(2,4-dimethylpentadienyl) complexes [Ln(η5-Me 2C5H5)3] (Ln = Nd, La, Y) are obtained analytically pure by reaction of the tribromides LnBr 3·THF with the potassium compound K(Mesub
