13813-22-4Relevant articles and documents
The first reduced rare earth halide with a group 11 element as interstitial: La3I3Au
Mattausch, Hansjuergen,Zheng, Chong,Kienle, Lorenz,Simon, Arndt
, p. 2367 - 2372 (2004)
The title compound was synthesized from La, LaI3 and Au under Ar atmosphere in the temperature range 850-950°C. It crystallizes in the cubic space group I4132 with lattice constant a = 12.661(2) A. The structure features Au-centered helical octahedron chains arranged in all three directions with 90 degree turns. It is the first reduced rare earth halide with a group 11 interstitial. It is very air and moisture sensitive, and produces crimson-colored Au precipitate similar to Gold Purple of Cassius upon reaction with water or ethanol.
Rare-earth iodides in ionic liquids: Crystal structures of [bmpyr]4[LnI6][Tf2N] (Ln = La, Er)
Babai, Arash,Mudring, Anja-Verena
, p. 122 - 127 (2006)
Deliberately designed ionic liquids can be excellent solvents for organic reactions with lanthanide compounds, e.g. Lewis catalysis with trivalent lanthanides. Little is known about the solvation and complexation of these Lewis-acid catalysts in these-still uncommon-solvents, although the knowledge of these processes is a prerequisite for a basic understanding of reaction mechanisms and catalytic cycles. Therefore, we have investigated the chemical behaviour of rare-earth metal iodides in the ionic liquid [bmpyr][Tf2N] (bmpyr = 1,1-n-butyl-methylpyrrolidinium; Tf2N = bis(trifluoromethanesulfonyl)-amide). Compounds of the general composition [bmpyr]4[LnI6][Tf2N] could be crystallized from solutions of LnI3 (Ln = La, Er), in [bmpyr][Tf2N]. Single-crystal X-ray diffraction data show that the trivalent rare-earth cations are octahedrally coordinated by six iodide anions. Eight cations of the ionic liquid are located tangentially above each of the triangular faces of the [LnI6] octahedron. According to the size of the trivalent cation, the crystal structure adjusts itself by tilting of the [LnI6] octahedra to accommodate one anion of the ionic liquid, bis(trifluoromethanesulfonyl)-amide, which completes the crystal structure of the composition [bmpyr]4[LnI6][Tf2N].
LiLa6I12Os, a substitutional derivative of rhombohedral La(La6I12Os)
Jensen, Elizabeth A.,Corbett, John D.
, p. 4465 - 4474 (2004)
The series of quaternary rare-earth-metal halide cluster compounds ALa 6I12Z with transition metal interstitials Z and alkali or alkaline-earth metal cations A has been expanded to include A=Li. The compounds synthesized by high-temperature solid-state techniques for Z=Os, Ir, Pt, Ru are isotypic with rhombohedral R7X12Z (R3, Z=3). The refined single X-ray crystal structure of (Li0.967La 0.033)La6I12Os is reported, along with supportive results from a Rietveld analysis of neutron powder diffraction from a different sample, 7Li MAS-NMR, and electronic resistivity and magnetic susceptibility measurements. The samples show continuous Li 1-xLax cation compositions and are generally semiconductors, but their complex paramagnetic properties are not those of simple spin-only systems.
The aluminide iodides La24Al12I21 and La10Al5I8: Compounds with intermetallic La-A1 fractions and La-Al clusters
Mattausch, Hansjuergen,Oeckler, Oliver,Hoch, Constantin,Simon, Arndt
, p. 1233 - 1238 (2006)
Reacting pieces of La, LaI3 and A1 filings (molar ratio 22: 8: 15) at 800 °C-825 °C results in La24Al12I 21 (70% yield) together with La10Al5I 8 (10 % yield), besides known La3Al2I 2 and La2Al2I. Both new compounds form golden coloured needles. La10Al5I8 is brittle, whereas La24Al12I21 is shaped as hair-like easily deformable bundles. Both are monoclinic, space group C2/m, La 24Al12I21 with a = 35.753(7) A, b = 4.327(1) A, c = 27.442(6) A, β = 116.62(3)° and La 10Al5I8 with a = 19.649(1) A, b = 4.296(1) A, c = 18.0290(1) A and β = 96.67(3)°. The La atoms form trigonal prisms condensed into double chains along [010]. The La prisms are centered by A1 atoms which form Al6 rings connected into chains. The La-Al strands are surrounded by I atoms in La24Al 12I21, whereas in La10Al5I 8 they are connected to form corrugated sheets separated by close packed layers of I atoms together with Al atoms. The octahedral voids around the Al atoms are occupied by La atoms, and such La6Al clusters are connected via opposite edges to octahedra chains along [010].
Substitution experiments on superconducting La2C2X2 (X = Cl, Br, I)
Ahn,Mattausch,Simon
, p. 619 - 622 (1997)
The layered carbide bromide La2C2Br2 becomes superconducting at 6.2 K. We studied the matrix effect on Tc due to (isoelectronic) halogen substitution. Tc increases with the amount of substitution by chlorine to a maximum value of 7.2 K, and it decreases when Br- is partially substituted by I-. La2C2I2 itself is non-superconducting down to 2 K. However, substitution of I- by 10% Cl- leads to superconductivity at 2.2 K.
The lanthanumiodideethanide o-La5I9(C2) - The orthorhombic high temperature modification
Mattausch, Hansjuergen,Hoch, Constantin,Simon, Arndt
, p. 641 - 645 (2008)
o-La5I9(C2) is synthesized by reaction of LaI3, La metal and graphite powder in sealed Ta containers at 850°C a = 8.0247(16) A, b = 16.887(3) A, c = 35.886(7) A. o-Ce5I9(C2) is isotypic with the lattice parameters a = 7.9284(4) A, b = 16.714(1) A, c = 35.530(3) A. o-La5I9(C2) transforms at 800°C to the triclinic low temperature modification t-La5I9(C 2). The transformation is reversible. The La atoms form trigonal bipyramids centered by C2 groups. These units are connected by iodine atoms above the faces (f), edges (e) and corners according to La 5(C2)I(f)iI(e)i-i 2/2I(e)i-a7/2I(e)a-i 7/2. The C-C distance in the C2 unit is 1.45(2) A. The crystals with greenish luster are moisture sensitive.
Lanthanide(III) halides: Thermodynamic properties and their correlation with crystal structure
Rycerz,Gaune-Escard
, p. 167 - 174 (2008/10/09)
Temperatures and enthalpies of phase transitions of 17 lanthanide(III) halides determined experimentally are reported. Correlations were made between temperature of fusion of lanthanide(III) halides, on the one hand, and enthalpy of fusion, on the other, versus atomic number of lanthanide. According to this classification, the lanthanide(III) halides split into groups, as also do the corresponding crystal structures. A correlation between the crystal structure of lanthanide(III) halides and their respective entropy of fusion (or entropy of fusion + entropy of solid-solid phase transition) was inferred from the aforementioned features. Fusion in those halides with hexagonal, UCl3-type and orthorhombic, PuBr3-type, structures entails an entropy of fusion change (or entropy of fusion + entropy of solid-solid phase transition change) by 50 ± 4 J mol-1 K-1. The homologous entropy change within the group of halides having the rhomboedric, FeCl3-type, structure, is smaller and equals 40 ± 4 J mol-1 K-1. Halides with monoclinic, AlCl3-type, crystal structure constitute a third group associated to an even smaller entropy change upon fusion, only 31 ± 4 J mol-1 K-1. The halides with lower entropies of fusion also have a lower S1300 K - S298 K indicating either a higher degree of order in the liquid or a higher entropy in the solid at room temperatures.
