Diffractometer Data Research Articles

Ternary rhombohedral Laves phases RE 2Rh3Ga (RE = Y, La–Nd, Sm, Gd–Er)

Abstract: The ordered Laves phases RE 2Rh3Ga (RE=Y, La–Nd, Sm, Gd–Er) were synthesized by arc-melting of the elements and subsequent annealing. The samples were characterized by powder X-ray diffraction (XRD). They crystallize with the rhombohedral Mg2Ni3Si type structure, space group R3̅m. Three structures were refined from single crystal X-ray diffractometer data: a=557.1(1), c=1183.1(2), wR2=0.0591, 159 F 2 values, 10 variables for Y2Rh3Ga, a=562.5(2), c=1194.4(2) pm, wR2=0.0519, 206 F 2 values, 11 variables for Ce2Rh3Ga and a=556.7(2), c=1184.1(3) pm, wR2=0.0396, 176 F 2 values, 11 variables for Tb2Rh3Ga. The Rh3Ga tetrahedra are condensed via common corners and the large cavities left by the network are filled by the rare earth atoms. The RE 2Rh3Ga Laves phases crystallize with a translationengleiche subgroup of the cubic RERh2 Laves phases with MgCu2 type. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y2Rh3Ga and La2Rh3Ga. Ce2Rh3Ga shows intermediate cerium valence while all other RE 2Rh3Ga phases are Curie–Weiss paramagnets which order magnetically at low temperatures. The 89Y and 71Ga solid state nuclear magnetic resonance (NMR) spectra of the diamagnetic representative Y2Rh3Ga show well-defined single resonances in agreement with an ordered bulk phase. In comparison to the binary Laves phase YRh2 a strongly increased 89Y resonance frequency is observed owing to a higher s-electron spin density at the 89Y nuclei as proven by density of states (DOS) calculations.

Equiatomic intermetallic compounds REPtMg (RE = Y, Eu, Tb-Tm, Lu) – Structure and magnetism

Eight new equiatomic REPtMg intermetallics with RE = Y, Eu, Tb-Tm, Lu were synthesized from the elements in sealed niobium ampoules (induction melting followed by different annealing sequences). All samples were characterized through X-ray powder patterns and the structures of YPtMg, EuPtMg, DyPtMg, HoPtMg and TmPtMg were refined from single crystal X-ray diffractometer data. The REPtMg phases crystallize with two different structure types. The representatives with RE = Y, Tb-Ho crystallize with the hexagonal ZrNiAl type, space group P6¯2m, while those with RE = Eu, Yb and Lu adopt the orthorhombic TiNiSi type, space group Pnma. ErPtMg and TmPtMg are dimorphic with a ZrNiAl type high and a TiNiSi type low-temperature modification. Temperature-dependent magnetic susceptibility measurements indicate Pauli paramagnetism for YPtMg and LuPtMg while EuPtMg, TbPtMg, DyPtMg and HoPtMg are Curie-Weiss paramagnets. Antiferromagnetic (TN = 12.6 K for EuPtMg) respectively ferromagnetic ordering (TC = 56.3 K for TbPtMg, 28.8 K for DyPtMg and 19.9 K for HoPtMg) occurs in the low-temperature regime. 151Eu Mössbauer spectra confirm divalent europium (δ = −8.03 mm s−1 at 78 K) in EuPtMg and show strong magnetic hyperfine field splitting below the Néel temperature.

A new solid solution compound with the Sr21Mn4Sb18 structure type: Sr13Eu8Cd3Mn1Sb18

Abstract The title compound with the nominal formula, Sr13Eu8Cd3Mn1Sb18, was synthesized by Sn-flux. Structure refinement was based on single-crystal X-ray diffractometer data. Employing the exact composition, the formula is Sr13.23Eu7.77Cd3.12Mn0.88Sb18 for the solid solution Sr21-xEuxCd4-yMnySb18. This phase adopts the Sr21Mn4Sb18 type structure with site preferences for both Eu and Cd. The structure crystallizes in the monoclinic system in space group C2/m and Z=4: a=18.1522(11), b=17.3096(10), c=17.7691(10) Å, β=91.9638(8)°, 6632 F2 values, 216 variables, R1=0.0254 and wR2=0.0563. Site selectivity of the elements in this new compound will be discussed in relationship with the Sr21Mn4Sb18 type structure and other related structure types. Temperature dependent magnetic susceptibility data reveal Curie–Weiss paramagnetism with an experimental moment of 19.3 μB/f.u. and a Weiss constant of 0.4 K. Magnetic ordering is seen at low temperatures, with a transition temperature of 3.5 K.

Ternary gallides RE 4Rh9Ga5, RE 5Rh12Ga7 and RE 7Rh18Ga11 (RE=Y, La–Nd, Sm, Gd, Tb) – intergrowth structures with MgCu2 and CaCu5 related slabs

Abstract Fourteen ternary gallides RE 4Rh9Ga5, RE 5Rh12Ga7 and RE 7Rh18Ga11 (RE=Y, La–Nd, Sm, Gd, Tb) were synthesized from the elements by arc-melting, followed by different annealing sequences either in muffle or induction furnaces. The samples were characterized through Guinier powder patterns and the crystal structures of Ce4Rh9Ga5, Ce5Rh12Ga7, Ce7Rh18Ga11, Nd5Rh10.44(4)Ga8.56(4), Nd4Rh9Ga5 and Gd4Rh9Ga5 were refined from single crystal X-ray diffractometer data. The new gallides are the n=2, 3 and 5 members of the RE 2+n Rh3+3n Ga1+2n structure series in the Parthé intergrowth concept. The slabs of these intergrowth structures derive from the cubic Laves phase MgCu2 (Mg2Ni3Si as ternary variant) and CaCu5 (CeCo3B2 as ternary variant). Only the Nd5Rh10.44(4)Ga8.56(4) crystal shows Rh/Ga mixing within the Laves type slabs. Magnetic susceptibility measurements reveal Pauli paramagnetism for Y4Rh9Ga5 and Curie-Weiss paramagnetism for Gd4Rh9Ga5 and Tb4Rh9Ga5. Low-temperature data show ferromagnetic ordering at T C=78.1 (Gd4Rh9Ga5) and 55.8 K (Tb4Rh9Ga5).

Crystal Structure, Magnetism, 89Y Solid State NMR, and 121Sb Mössbauer Spectroscopic Investigations of YIrSb

The ternary antimonide YIrSb was synthesized from the binary precursor YIr and elemental antimony by a diffusion controlled solid‐state reaction. Single crystals were obtained by a flux technique with elemental bismuth as an inert solvent. The YIrSb structure (TiNiSi type, space group Pnma) was refined from single‐crystal X‐ray diffractometer data: a = 711.06(9), b = 447.74(5), c = 784.20(8) pm, wR2 = 0.0455, 535 F2 values, 20 variables. 89Y solid state MAS NMR and 121Sb Mössbauer spectra show single resonance lines in agreement with single‐crystal X‐ray data. YIrSb is a Pauli paramagnet.

Poly[di-μ2-acetato-κ4O:O′-μ3-thiourea-κ3S:S:S-lead(II)]: a redetermination

The structure of the title polymeric lead(II) thiourea complex, [Pb(CH3O)2{SC(NH2)2}]n, has been redetermined at significantly higher precision using diffractometer data at 100 K. The previous determination used data obtained from multiple-film integrated Weissenberg photographs [Nardelliet al.(1960).Acta Cryst.13, 898–904]. The main difference between the two models is in the precision of the bond lengths, angles and cell parameters. In the crystal, the eight-coordinate PbIIatom is chelated by two carboxylate groups and bridged by three S atoms from thiourea ligands. The coordination sphere is completed by an O atom from a third carboxylate group, the second O atom of which binds to a neighbouring PbIIatom, forming a polymeric chain that runs theaaxis. Two of these chains are related by centres of symmetry. Intermolecular hydrogen bonds connect neighbouring chains to one another, generating a three-dimensional network.

Indides RE 3 T 2In4 (RE = Y, Gd–Tm, Lu; T = Ni, Ru, Rh) with a ZrNiAl superstructure

Abstract Three series of rare earth-transition metal-indides RE 3 T 2In4 (RE=Y, Gd–Tm, Lu; T=Ni, Ru, Rh) were synthesized from arc-melted RE 3 T 2 precursor compounds and indium tear shot in sealed niobium ampoules using different annealing sequences. The new indides crystallize with the hexagonal Lu3Co2In4-type structure, space group P6̅. All samples were characterized on the basis of Guinier powder patterns and six structures were refined from single crystal X-ray diffractometer data. The RE 3 T 2In4 structures are derived from the ZrNiAl type through RE/In ordering, paralleled by a symmetry reduction from P6̅2m to P6̅. This induces twinning for some of the investigated crystals. The main crystal chemical motifs of the RE 3 T 2In4 structures are trigonal prisms of rare earth, respectively indium atoms that are filled by the transition metals.

Li2Pt3Se4: a new lithium platinum selenide with jaguéite-type crystal structure by multianvil high-pressure/high-temperature synthesis

Abstract The monoclinic lithium platinum selenide Li2Pt3Se4 was obtained via a multianvil high-pressure/high-temperature route at 8 GPa and 1200°C starting from a stoichiometric mixture of lithium nitride, selenium, and platinum. The structure of the ternary alkali metal-transition metal-selenide was refined from single-crystal X-ray diffractometer data: P21/c (no. 14), a=525.9(2), b=1040.6(2), c=636.5(2) pm, β=111.91(1)°, R1=0.0269, wR2=0.0569 (all data) for Li2Pt3Se4. Furthermore, the isostructural mineral phases jaguéite (Cu2Pd3Se4) and chrisstanleyite (Ag2Pd3Se4) were reinvestigated in their ideal stoichiometric ratio. The syntheses of the mineral phases were also carried out under multianvil conditions. Single-crystal data revealed a hitherto not described structural disorder of the transition metal atoms.

Monoclinic superstructure of Pr3Rh4Ge4

Abstract Pr3Rh4Ge4 was synthesized by melting of the elements in an arc-melting furnace followed by annealing in a sealed tantalum ampoule in a muffle furnace. Structure refinement was based on temperature dependent single-crystal X-ray diffractometer data. At ambient temperature Pr3Rh4Ge4 adopts the U3Ni4Si4 type structure with strongly enhanced anisotropic displacement parameters for Rh1. Below 230 K additional reflections start to appear and at 110 K the structure could be described with the (3+1)D superspace group I2/m(α0γ)00; α=1/2, γ=1/2; (Z=2). This commensurately modulated structure could be refined with 1448 F 2 values, 39 variables and residuals of wR=0.0417 for the main reflections and wR=0.1520 for the satellites of 1st order, [a=408.36(2), b=421.12(3) and c=2504.4(2) pm]. The commensurate description could be transformed to a 3D supercell with space group A2/m and Z=4: a=816.72(2), b=421.12(3), c=2537.5(1) pm, β=99.26(1)°, 1448 F 2 values, 69 variables and wR=0.0499. The relation of the U3Ni4Si4 type structure, the (3+1)D modulated and the 3D supercell is discussed on the basis of a group–subgroup scheme. Temperature dependent magnetic susceptibility data reveal Curie–Weiss paramagnetism with an experimental moment of 3.72(2) μB/Pr atom and a Weiss constant of –12.6(5) K. No magnetic ordering is evident down to 3 K.

The quaternary arsenide oxides Ce9Au5–x As8O6 and Pr9Au5–x As8O6

Abstract The quaternary gold arsenide oxides Ce9Au5−x As8O6 and Pr9Au5−x As8O6 were synthesized from the rare earth elements (RE), rare earth oxides, arsenic and gold powder at maximum annealing temperatures of 1173 K. The structures were refined from single crystal X-ray diffractometer data: Pnnm, a=1321.64(6) pm, b=4073.0(3), c=423.96(2), wR2=0.0842, 3106 F 2 values, 160 variables for Ce9Au4.91(4)As8O6 and Pnnm, a=1315.01(4), b=4052.87(8), c=420.68(1) pm, wR2=0.0865, 5313 F 2 values, 160 variables for Pr9Au4.75(1)As8O6. They represent a new structure type and show a further extension of pnictide oxide crystal chemistry. A complex polyanionic gold arsenide network [Au5As8]15− (with some disorder in the gold substructure) is charge compensated with polycationic strands of condensed edge-sharing O@RE 4/4 and O@RE 4/3 tetrahedra ([RE 4O3]2 12+) as well as RE 3+ cations in cavities.

High-pressure high-temperature decomposition of CeCoGa to the Laves phases CeCo0.58Ga1.42, CeCo0.72Ga1.28, and CeCo2

Abstract The monoclinic intermediate-valent gallide CeCoGa decomposes under high-pressure (HP) (9.5 GPa) high-temperature (HT) (1470 K) conditions into the Laves phases CeCo0.58Ga1.42 (MgCu2 type), CeCo0.72Ga1.28 (MgZn2 type; major product phase), and CeCo2 (MgCu2 type). The structures of the ternary Laves phases were refined from single crystal X-ray diffractometer data: Fd3̅m, a=778.3(1) pm, wR2=0.0310, 63 F 2 values, five variables for CeCo0.58(3)Ga1.42(3) and P63/mmc, a=547.24(5), c=858.76(7) pm, wR2=0.1009, 195 F 2 values, 13 variables for CeCo0.72(1)Ga1.28(1). Partial substitution of cobalt by gallium leads to a significant increase of the distances within the tetrahedral network: 253 pm Co–Co in CeCo2 as compared to 275 pm in CeCo0.58(3)Ga1.42(3) and 265–277 pm in CeCo0.72(1)Ga1.28(1). The crystal chemical consequences are briefly discussed.

Ternary germanides RERhGe2 (RE = Y, Gd-Ho) – New representatives of the YIrGe2 type

The YIrGe2 type ternary germanides RERhGe2 (RE = Y, Gd-Ho) were synthesized from the elements by arc-melting and characterized by powder X-ray diffraction. The structure of DyRhGe2 was refined from single crystal X-ray diffractometer data: Immm, a = 426.49(9), b = 885.0(2), c = 1577.4(3) pm, wR2 = 0.0533, 637 F2 values, 30 variables (300K data). The structure contains two crystallographically independent dysprosium atoms in pentagonal prismatic and hexagonal prismatic coordination. The three-dimensional [RhGe2] polyanion is stabilized through covalent Rh–Ge (243–261pm) and Ge–Ge (245–251pm) bonding. The close structural relationship with the slightly rhodium-poorer germanides RE5Rh4Ge10 (≡ RERh0.8Ge2) is discussed. Temperature-dependent magnetic susceptibility measurements reveal Pauli paramagnetism for YRhGe2 and Curie-Weiss paramagnetism for RERhGe2 with RE = Gd, Tb, Dy and Ho. These germanides order antiferromagnetically at TN = 7.2(5), 10.6(5), 8.1(5), and 6.4(5) K, respectively.

Quaternary Germanides RE3TRh4Ge4 (RE = Ce, Pr, Nd; T = Nb, Ta) – A New Coloring Variant of the Aristotype AlB2

AbstractThe quaternary germanides RE3TRh4Ge4 (RE = Ce, Pr, Nd; T = Nb, Ta) were synthesized from the elements by arc‐melting and subsequent annealing in a muffle furnace. The structure of Ce3TaRh4Ge4 was refined from single‐crystal X‐ray diffractometer data: new type, Pbam, a = 719.9(2), b = 1495.0(3), c = 431.61(8), wR2 = 0.0678, 1004 F2 values, and 40 variables. Isotypy of the remaining phases was evident from X‐ray powder patterns. Ce3TaRh4Ge4 is a new superstructure variant of the aristotype AlB2 with an ordering of cerium and tantalum on the aluminum site, whereas the honey‐comb network is built up by a 1:1 ordering of rhodium and germanium. This crystal‐chemical relationship is discussed based on a group‐subgroup scheme. The distinctly different size of tantalum and cerium leads to a pronounced puckering of the [Rh4Ge4] network, which shows the shortest interatomic distances (253–271 pm Rh–Ge) within the Ce3TaRh4Ge4 structure. Another remarkable structural feature concerns the tantalum coordination with six shorter Ta–Rh bonds (265–266 pm) and six longer Ta–Ge bonds (294–295 pm). The [Rh4Ge4] network fully separates the tantalum and cerium atoms (Ce–Ce > 387 pm, Ta–Ta > 431 pm, and Ce–Ta > 359 pm). The electronic density of states DOS from DFT calculations show metallic behavior with large contributions of localized Ce 4f as well as itinerant ones from all constituents at the Fermi level but no significant magnetic polarization on Ce could be identified. The bonding characteristics described based on overlap populations illustrate further the crystal chemistry observations of the different coordination of Ce1 and Ce2 in Ce3TaRh4Ge4. The Rh–Ge interactions within the network are highlighted as dominant. The bonding magnitudes follow the interatomic distances and identify differences of Ta bonding vs. Ce1/Ce2 bonding with the Rh and Ge substructures.

Gallium‐Indium Ordering in the Complex [Ni2Ga3In] Network of GdNi2Ga3In

AbstractPolycrystalline samples of the isotypic quaternary compounds RENi2Ga3In (RE = Y, Gd – Tm) were obtained by arc‐melting of the elements. Crystals of the gadolinium compound were found by slow cooling of an arc‐melted button of the initial composition “GdNiGa3In”. All samples were characterized by powder X‐ray diffraction. The structure of GdNi2Ga2.89In1.11 was refined from single‐crystal X‐ray diffractometer data: new type, Pnma, a = 2426.38(7), b = 418.17(2), c = 927.27(3) pm, wR2 = 0.0430, 1610 F2 values and 88 variables. Two of the six crystallographically independent gallium sites show a small degree of Ga/In mixing. The nickel atoms show tricapped trigonal prismatic coordination by gadolinium, gallium, and indium. Together, the nickel, gallium, and indium atoms build up a complex three‐dimensional [Ni2Ga3In]δ– network, which leaves cages for the gadolinium atoms. The indium atoms form zigzag chains with In–In distances of 337 pm. The crystal chemical similarities of the polyhedral packing in the GdNi2Ga3In and La4Pd10In21 structures are discussed.

Structural, dielectric and vibrational studies of the new mixed solid solution of thallium potassium sulfate selenate tellurate

The new mixed compound Tl1.89K0.11(SO4)0.9(SeO4)0.1Te(OH)6 which is crystallized in the monoclinic system with space group P21/c was analyzed at room temperature using X-ray diffractometer data. The unit cell parameters are a = 12.3308(7), b = 7.2011(4), c = 12.0298(8) A, β = 110.755(4)°, V = 998.87(11) A3 and Z = 4. The final refinement led to R = 0.035 and Rw = 0.038. The main feature of these atomic arrangements is the coexistence of three and different anions (SO42−, SeO42− and TeO66− groups) in the unit cell, connected by hydrogen bonds (O–H···O) which make the building of the crystal. The Tl+ and K+ cations, occupying the same positions, are located between these polyhedral. The crystals of Tl1.89K0.11(SO4)0.9(SeO4)0.1Te(OH)6 underwent three endothermic peaks at 377, 466 and 472 K. These transitions were detected by DSC and analyzed by dielectric measurements using the impedance and modulus spectroscopy techniques. The IR and Raman spectra recorded at room temperature in the frequency ranges (50–1200) and (400–4000) cm−1, respectively, have confirmed the presence of TeO66−, SO42− and SeO42− groups in the crystal.

Ternary silicides ScIr4Si2 and RERh4Si2 (RE = Sc, Y, Tb-Lu) and quaternary derivatives RERh4Si2–xSnx (RE = Y, Nd, Sm, Gd-Lu) – structure, chemical bonding, and solid state NMR spectroscopy

Abstract The silicides ScIr4Si2 and RERh4Si2 (RE=Sc, Y, Tb-Lu) and silicide stannides RERh4Si2–x Sn x (RE=Y, Nd, Sm, Gd-Lu) were synthesized from the elements by arc-melting and subsequent annealing. The new compounds crystallize with the orthorhombic YRh4Ge2 type structure, space group Pnma. They were characterized by X-ray powder patterns and several structures were refined from single crystal X-ray diffractometer data. The main structural motifs of this series of silicides are tricapped trigonal prisms formed by the transition metal and rare earth atoms. One of the two crystallographically independent silicon sites allows for formation of solid solutions with tin, exemplarily studied for ErRh4Si2–x Sn x . Electronic structure calculations reveal strong covalent Rh–Si bonding as the main stability factor. Multinuclear (29Si, 45Sc, and 89Y) magic-angle spinning (MAS) NMR spectra of the structure representatives with diamagnetic rare-earth elements (Sc, Y, Lu) are found to be consistent with the crystallographic data and specifically confirm the selective substitution of Sn in the Si2 sites in the quaternary compounds YRh4SiSn and LuRh4SiSn.

YPd2Al and YPd2Zn with LiCu2Sn Type Structure

AbstractThe palladium‐rich phases YPd2Al and YPd2Zn were synthesized from the elements; YPd2Al by arc‐melting and YPd2Zn by induction melting in a sealed niobium ampoule. The structure of YPd2Al was refined from single‐crystal X‐ray diffractometer data: LiCu2Sn type, P63/mmc, a = 433.9(2), c = 910.5(2) pm, wR2 = 0.0497, 150 F2 values, and 9 variables. The lattice parameters of YPd2Zn are a = 437.3(1) and c = 891.4(2) pm. The aluminum atoms in YPd2Al show strongly flattened octahedral palladium coordination. These AlPd6 octahedra are condensed via edges, forming layers around z = 0 and z = 1/2, which are condensed in c direction by weak Pd–Pd bonds. The yttrium atoms fill the cavities between these layers. YPd2Al and YPd2Zn belong to a larger family of 341 compounds with the Wyckoff sequence 194,fca. The distinctly different crystal chemical branches are briefly discussed.

Ni4 and Ni3Ga clusters as building units in Ca3Ni4Ga4 and Sr3Ni3□Ga4

Abstract The gallides Ca3Ni4Ga4 and Sr3Ni3Ga4 were synthesized from arc-melted NixGay precursor alloys and the respective alkaline earth metal in sealed niobium tubes in an induction furnace. Redetermination of the Ca3Ni4Ga4 structure from X-ray single crystal diffractometer data confirmed the X-ray powder data: Na3Pt4Ge4 type, I4̅3m, a=740.6(1) pm, wR2=0.0245, 169 F2 values, 9 variables. The nickel atoms build tetrahedral Ni4 clusters (256 pm Ni–Ni) that are end-on coordinated by gallium atoms (234 pm Ni–Ga). These [Ni4Ga4] units show a bcc packing and leave cavities Ca@Ga4Ni4Ga4 for the calcium atoms. Sr3Ni3Ga4 crystallizes with a new structure type: R3m, a=1039.8(2), c=698.2(1) pm, wR2=0.1048, 636 F2 values, 23 variables. The structure shows twinning by inversion with a domain ratio of 79/21. The structures of Sr3Ni3Ga4 and Ca3Ni4Ga4 are related by a group–subgroup scheme (R3m is a translationengleiche subgroup of I4̅3m). The 8c Ni and Ga subcell sites split into site 3a and 9b each. This allows formation of ordered Ni3Ga tetrahedra (264 pm Ni–Ga) along with ordered gallium vacancies.

Triangular Zn3and Ga3units in Sr2Au6Zn3, Eu2Au6Zn3, Sr2Au6Ga3, and Eu2Au6Ga3– structure, magnetism,151Eu Mössbauer and69;71Ga solid state NMR spectroscopy

AbstractThe gold-rich intermetallic compounds Sr2Au6Zn3, Eu2Au6Zn3, Sr2Au6Ga3, and Eu2Au6Ga3were synthesized from the elements in sealed tantalum ampoules in induction or muffle furnaces. The europium compounds are reported for the first time and their structures were refined from single crystal X-ray diffractometer data: Sr2Au6Zn3type,R3̅c,a= 837.7(1),c= 2184.5(4) pm,wR2 = 0.0293, 572F2values for Eu2Au6.04Zn2.96anda= 838.1(2),c= 2191.7(5) pm,wR2 = 0.0443, 513F2values for Eu2Au6.07Ga2.93with 20 variables per refinement. The structures consist of a three-dimensional gold network with a 6R stacking sequence, similar to the respective diamond polytype. The cavities of the network are filled in a ratio of 2:1 by strontium (europium) atoms and Ga3(Zn3) triangles in an ordered manner. Sr2Au6Zn3and Sr2Au6Ga3are diamagnetic with room temperature susceptibilities of –3.5 × 10−4emu mol–1. Temperature dependent susceptibility and151Eu Mössbauer spectroscopic measurements show a stable divalent ground state for both europium compounds. Eu2Au6Zn3and Eu2Au6Ga3order antiferromagnetically below Néel temperatures of 16.3 and 12.1 K, respectively. Anisotropic electrical conductivity of Sr2Au6Ga3is proven by an alignment of the crystallites in the magnetic field. Orientation-dependent69;71Ga NMR experiments combined with quantum mechanical calculations (QM) give evidence for a highly anisotropic charge distribution of the Ga atoms.

Hydrogenation studies on NdScSi and NdScGe

NdScSi and NdScGe were synthesized from the elements via arc-melting and subsequent annealing. Their ordered La2Sb type structures, with space group I4/mmm, were refined from single crystal X-ray diffractometer data: a=428.94(6) and b=1570.5(3)pm, wR2=0.0395, 309 F2 values for NdScSi and a=431.2(1) and c=1581.3(5)pm, wR2=0.1220, 227 F2 values for NdScGe, with 11 variables per refinement.Hydrogen insertion was performed on both Nd-based intermetallics by solid/gas reaction. Hydrogen uptake keeps the pristine compound space group but yields an anisotropic expansion of the unit cell with a large increase of c (≈+7%) and a slight decrease of a (≈−1.7%) parameters. Hydrogen absorption at 350°C and under 5bar of H2 pressure shows that the hydride NdScSiH1.48(5) is formed. An in-situ neutron diffraction study during the deuteration of NdScSi reveals for the first time in a CeScSi-type compound, the possibility to fill two interstitial sites with deuterium atoms, leading to the composition NdScSiD1.5 for the deuteride adopting then the La2Fe2Se2O3-type structure.From magnetization measurements, we evidence that hydrogenation strongly reduces the Curie temperature of NdScSi (TC=175K) and NdScGe (TC=194K) since NdScSiH1.5 and NdScGeHx undergo a magnetic transition at 4K and around 2K, respectively.