13536-53-3Relevant academic research and scientific papers
Planar B4 rhomboids: The rare earth boride halides RE4X5B4
Mattausch,Simon,Felser
, p. 9951 - 9957 (1997)
The new compounds RE4X5B4 (RE = La, Ce, Pr, Gd and X = Br, I) and RE4I5B2C (RE = La, Ce) are prepared via the reaction of RE metal, REX3 and B, or B and C at temperatures 1670 ≥ T ≥ 1270 K in welded tantalum ampoules. Chains of interconnected B4 rhomboids are the characteristic features of the crystal structures. According to band structure calculations, the compounds are one-dimensional metals which undergo a gradual metal-to-semiconductor transition at low temperature as experimentally indicated by the steep inrease of electrical resistivity.
The Starting Members of the Series Pr4n+2(C2) nBr5n+5(n = 1, 2, 3)
Schaloske, Manuel Christian,Mattausch, Hansjürgen,Duppel, Viola,Kienle, Lorenz,Simon, Arndt
, p. 922 - 928 (2009)
The compounds Pr6(C2)Br10, Pr 10(C2)2Br15 and Pr 14(C2)3Br20 were prepared from PrBr3 and the appropriate amounts of Pr and C and char
The enthalpies of formation of praseodymium halides PrCl3, PrBr3, and PrI3 in the crystalline state and aqueous solution
Goryushkina,Monaenkova,Popova,Tiflova
, p. 1710 - 1713 (2006)
The enthalpies of solution of praseodymium tribromide and triiodide in water were measured at 298.15 K in a hermetic isothermic-shell swinging calorimeter. The data obtained and the Δf H° (Pr 3+, sln, ∞H2O, 298 K) value found earlier were used to calculate the enthalpies of formation of three praseodymium halides (PrCl3, PrBr3, and PrI3) in the crystalline state and aqueous solution. Nauka/Interperiodica 2006.
High temperature phase and thermal expansion of PrBr3
Kraemer, Karl W.,Keller, Lukas
, p. 982 - 987 (2009)
The thermal expansion and phase transition of PrBr3 was investigated by neutron diffraction and DSC measurements. PrBr3 has a low-temperature (LT) UCl3-type modification and a high-temperature (HT) PuBr3-type mo
Thermodynamic and transport properties of the PrBr3-RbBr binary system
Rycerz, Leszek,Ingier-Stocka, Ewa,Berkani, Madjid,Gaune-Escard, Marcelle
, p. 269 - 274 (2010)
Phase equilibrium in the PrBr3RbBr binary system was established by differential scanning calorimetry (DSC). This system, investigated for the first time, includes Rb3PrBr6, Rb2PrBr 5 and RbPr2Br7 compounds, and three eutectics located at molar fraction of PrBr3 (x = 0.136; 865 K), (x = 0.488; 765 K) and (x = 0.679; 834 K), respectively. Rb3PrBr6 undergoes a solidsolid phase transition at 704K and melts congruently at 995 K. Rb2PrBr5 melts incongruently at 803K and finally RbPr2Br7 melts congruently at 852 K. The electrical conductivity of PrBr3RbBr liquid mixtures was measured over an extended temperature range down to temperatures below solidification and over the whole composition range. Results obtained are discussed in terms of possible complex formation.
M3NS3 (M = La - Nd, Sm, Gd - Dy): Structure and magnetism of 3:1:3-type nitride sulfides of trivalent lanthanides
Lissner, Falk,Meyer, Monika,Kremer, Reinhard K.,Schleid, Thomas
, p. 1995 - 2002 (2006)
Nitride sulfides of the trivalent lanthanides with the composition M 3NS3 (M = La - Nd, Sm, Gd - Dy) can be prepared by the oxidation of the respective lanthanide metal with sulfur, sodium azide (NaN 3), and the corresponding lanthanide tribromide (MBr3) when an additional flux (NaBr) is used. Temperature ranges from 800 to 900 °C for the thermal treatment of the reaction mixtures in evacuated silica tubes secure the formation of bright to dark brown, transparent, lath shaped single-crystals. The orthorhombic crystal structure (Pnma, Z = 4) was determined from single-crystal X-ray diffraction data (La3NS3: a = 1215.13(5), b = 415.90(2), c = 1322.12(5) pm, Ce3NS3: a = 1206.28(4), b = 410.16(1), c = 1307.18(5) pm, Pr3NS3: a = 1205.45(7), b = 405.35(2), c = 1297.58(8) pm, Nd3NS3: a = 1207.82(5), b = 401.31(1), c = 1295.20(4) pm, Sm3NS3: a = 1201.58(6), b = 394.84(2), c = 1285.63(7) pm, Gd3NS3: a = 1197.17(7), b = 388.22(3), c = 1286.92(8) pm, Tb3NS3: a = 1191.62(7), b = 385.07(3), c = 1282.44(8) pm, and Dy3NS3: a = 1187.66(7), b = 382.55(3), c = 1276.77(8) pm). There are three crystallographically different M3+ cations present in coordination of both the N3- and the S2- anions. However, [NM 4]9+ tetrahedra connected via two common corners (c) to form linear chains ∞1{[N(M1)1/1 t(M2)1/1t(M3)2/2c] 6+} along [010] build up the main structural feature. A non-linear behaviour for the decreasing lattice constants of the pseudo-isotypic series from La3NS3 to Dy3NS3 concerning the a- and c-axes is observed along with the lanthanoid contraction caused by the diminishing coordination sphere of (M1)3+ (CN = 7) and (M3) 3+ (CN = 7) moving from the light to the heavier lanthanides. Curie-Weiss-type magnetic behaviour for Dy3NS3 with μeff = 10.3(1) μB for DyN1/3S corresponding to a 6H15/2 groundstate for Dy3+ at higher temperatures and antiferromagnetic ordering of the Dy3+ moments below 5 K is observed.
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.
Pr6C2-bitetrahedra in Pr6C 2Cl10 and Pr6C2Cl5Br 5
Schaloske, Manuel C.,Mattausch, Hansjuergen,Kienle, Lorenz,Simon, Arndt
, p. 1493 - 1500 (2009/05/09)
The compounds Pr6C2Cl10 and Pr 6C2Cl5Br5 are prepared by heating stoichiometric mixtures of Pr, PrCl3, PrBr3 and C in sealed Ta capsules at 810-820°C. They form bulky transparent yellow to green and moisture sensitive crystals which have different structures: space groups C2/c, (a = 13.687(3) A, b = 8.638(2) A, c = 15.690(3) A, β = 97.67(3)° for Pr6C2Cl10 and a = 13.689(1) A, b = 10.383(1) A, c = 14.089(1) A, β = 106.49(1)° for Pr6C2Cl5Br5). Both crystal structures contain C-centered Pr6C2 bitetrahedra, linked via halogen atoms above edges and corners in different ways. The site selective occupation of the halogen positions in Pr 6C2Cl5Br5 is refined in a split model and analysed with the bond length-bond strength formalism. The compound is further characterized via TEM investigations and magnetic measurements (μeff = 3.66 μB).
Systematics and anomalies in rare earth/aluminum bromide vapor complexes: Thermodynamic properties of the vapor complexes LnAl3Br12 from Ln = Sc to Ln = Lu
Wang, Zhi-Chang,Yu, Jin
, p. 4248 - 4255 (2008/10/09)
Systematics and anomalies in the rare earth/aluminum bromide vapor complexes have been investigated by the phase equilibrium-quenching experiments. The measurements suggest that the LnAl3Br12 complexes are the predominant vapor compl
Pr4N2S3 and Pr4N 2Se3: Two non-isostructural praseodymium(III) nitride chalcogenides
Lissner, Falk,Schleid, Thomas
, p. 427 - 432 (2008/10/09)
The non-isostructural nitride chalcogenides of praseodymium, Pr 4N2S3 and Pr4N2Se 3, are formed by the reaction of the praseodymium metal with sodium azide (NaN3), praseodymium trihalide (PrX3; X = Cl, Br, I) and the respective chalcogen (sulfur or selenium) at 900°C in evacuated silica ampoules after seven days. Both crystallize monoclinically in space group C2/c (Pr4N2S3: a = 1788.57(9), b = 986.04(5), c = 1266.49(6) pm, β = 134.546(7)°, Z = 8; Pr4N 2Se3: a = 1311.76(7), b = 1017.03(5), c = 650.42(3) pm, β = 90.114(6)°, Z = 4). The crystal structures of both compounds show a layered construction, dominated by N3--centred (Pr 3+)4 tetrahedra which share a common edge first. Continuing linkage of the so resulting bitetrahedral [N2Pr 6]12+ units via the non-connected vertices to layers according to ∞2{[N(Pr)2/2 e(Pr')2/2v]3+} forms different kinds of tetrahedral nets which can be described as layers consisting of four- and eight-rings for Pr4N2S3 and as layers of six-rings for Pr4N2Se3. Whereas the crystal structure of Pr4N2S3 exhibits four different Pr3+ cations with coordination numbers of six (2x) and seven (2x) against N3- and S2-, the number of cations in the nitride selenide (Pr4N2Se3) is reduced to half (Pr1 and Pr2) also having six- and sevenfold anionic coordination spheres. Further motifs for the connection of [NM4]9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare-earth elements with ratios of N:M = 1:2 are presented and discussed.
