Synthesis and Structure of YbCuGe and YbIrGe

The equiatomic ytterbium–transition metal–germanides YbCuGe and YbIrGe were synthesized in single crystalline form from CuGe and IrGe master alloys and ytterbium via the Bridgman technique and they were characterized through their X-ray powder patterns. The structures were refined from X-ray single crystal diffractometer data: NdPtSb type, P6₃mc, a=421.36(8), c=703.9(1) pm, wR2=0.0234, 210 F² values, 11 variable parameters, BASF=0.35(9) for YbCuGe and TiNiSi type, Pnma, a=671.09(6), b=421.55(5), c=757.16(7) pm, wR2=0.0782, 519 F² values, 20 variable parameters for YbIrGe. The copper (iridium) and germanium atoms build up [CuGe] and [IrGe] networks. In YbCuGe the two-dimensional [CuGe] network consists of puckered layers of Cu₃Ge₃ hexagons (247pm Cu–Ge) that are charge balanced and separated by the ytterbium atoms. In contrast, the ordered Ir₃Ge₃ hexagons show a strong orthorhombic distortion and the [IrGe] network is three-dimensional with a distorted tetrahedral germanium coordination around iridium with almost equal Ir–Ge distances (252–259pm). The ytterbium atoms fill cages within this network. The cell volumes of YbCuGe and YbIrGe are indicative for purely trivalent ytterbium.     

Synthesis, Structure, and Magnetic Properties of the Silicides REIrSi ( RE = Ce, Pr, Er, Tm, Lu) and SmIr 0.266(8)Si 1.734(8)

The equiatomic rare earth metal–iridium–silicides REIrSi (RE=Ce, Pr, Er, Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. All silicides were characterized through their X-ray powder patterns. The structures of CeIrSi, ErIrSi, and LuIrSi were refined from X-ray single crystal diffractometer data: LaIrSi type, P2₁3, a=629.15(2)pm, wR2=0.1232, 280F² values, and 11 variable parameters for CeIrSi; TiNiSi type, Pnma, a=673.4(1), b=416.07(5), c=744.88(9)pm, wR2=0.0705, 339F² values, and 20 variable parameters for ErIrSi, and a=664.0(3), b=412.9(1), c=742.6(1)pm, wR2=0.0398, 496F² values, and 20 variable parameters for LuIrSi. The iridium and silicon atoms in CeIrSi, ErIrSi, and LuIrSi build three-dimensional [IrSi] networks where the iridium atoms have three (CeIrSi, Ir–Si 229pm) and four (ErIrSi, Ir–Si 247–258pm; LuIrSi, Ir–Si 245–256pm) silicon neighbors. The [IrSi] networks leave larger channels in which the cerium, erbium, and lutetium atoms are located. Temperature dependent susceptibility data for LuIrSi indicate Pauli paramagnetism. CeIrSi shows Curie-Weiss paramagnetism above 100K with an experimental magnetic moment of 2.56(2)_B/Ce atom. With samarium as rare earth metal component the silicide SmIr_0.266(8)Si_1.734(8) with -ThSi₂ type structure was obtained: I4₁/amd, a=409.3(1), c=1397.2(5)pm, wR2=0.0575, 161F² values, and 9 variable parameters. Within the three-dimensional [Ir_0.266Si_1.734] network the Ir/Si–Ir/Si distances range from 230 to 237pm.     

Crystal structure and specific heat of GdCuGe

A single crystal study of GdCuGe revealed full copper-germanium ordering: NdPtSb type, space group P6₃mc, a=423.2(1), , wR₂=0.0443, 414 F² values and 10 variables. The copper and germanium atoms build up two-dimensional networks of ordered [Cu₃Ge₃] hexagons with Cu-Ge distances of 244 pm. Consecutive [Cu₃Ge₃] layers are rotated by 60° around the perpendicular c-axis with respect to each other. The [Cu₃Ge₃] hexagons show a weak puckering. Heat capacity measurements on the polycrystalline sample of GdCuGe establishes antiferromagnetic ordering around 14 K in agreement with reports in the literature. The curves of heat capacity measured in different applied fields crosses each other at two well-defined points exhibiting a behavior usually associated with heavy fermion compounds. The results of the structural analysis and heat capacity measurements are discussed in the light of these interesting observations for a gadolinium intermetallic.     

Ternary Germanides RE 2Ge2Mg (REY, La–Nd, Sm, Gd, Tb)

Summary. The ternary rare earth metal-magnesium-germanides RE₂Ge₂Mg (RE=Y, La–Nd, Sm, Gd, Tb) were synthesized by reaction of the elements in sealed tantalum tubes in a water-cooled sample chamber of an induction furnace. The germanides were characterized through their X-ray powder patterns. The structures of Ce₂Ge₂Mg and Pr₂Ge₂Mg were refined from X-ray single crystal diffractometer data: Mo₂FeB₂ type, P4/mbm, a=750.6(1), c=442.4(1)pm, wR2=0.0378, 386 F² values, 12 variable parameters for Ce₂Ge₂Mg, and a=745.7(1), c=439.2(1)pm, wR2=0.0462, 448 F² values, 12 variable parameters for Pr₂Ge₂Mg. The lanthanum compound shows a homogeneity range La_2+xGe₂Mg_1–x. The structure of a single crystal with x=0.249(5) was refined from X-ray data: a=770.52(7), c=447.4(1)pm, wR2=0.0481, 322 F² values, 13 variable parameters. The RE₂Ge₂Mg structures can be considered as a 1:1 intergrowth of CsCl and AlB₂ related slabs of compositions REMg and REGe₂.     

Synthesis,Structure, and Magnetic Properties of the Silicides <Emphasis Type="BoldItalic">RE</Emphasis>IrSi (<Emphasis Type="Italic">RE</Emphasis> = Ce,Pr, Er,Tm, Lu) and SmIr<Subscript>0.266(8)</Subscript>Si<Subscript>1.734(8)</Subscript>

Summary. The equiatomic rare earth metal–iridium–silicides REIrSi (RE=Ce, Pr, Er, Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. All silicides were characterized through their X-ray powder patterns. The structures of CeIrSi, ErIrSi, and LuIrSi were refined from X-ray single crystal diffractometer data: LaIrSi type, P2₁3, a=629.15(2)pm, wR2=0.1232, 280F² values, and 11 variable parameters for CeIrSi; TiNiSi type, Pnma, a=673.4(1), b=416.07(5), c=744.88(9)pm, wR2=0.0705, 339F² values, and 20 variable parameters for ErIrSi, and a=664.0(3), b=412.9(1), c=742.6(1)pm, wR2=0.0398, 496F² values, and 20 variable parameters for LuIrSi. The iridium and silicon atoms in CeIrSi, ErIrSi, and LuIrSi build three-dimensional [IrSi] networks where the iridium atoms have three (CeIrSi, Ir–Si 229pm) and four (ErIrSi, Ir–Si 247–258pm; LuIrSi, Ir–Si 245–256pm) silicon neighbors. The [IrSi] networks leave larger channels in which the cerium, erbium, and lutetium atoms are located. Temperature dependent susceptibility data for LuIrSi indicate Pauli paramagnetism. CeIrSi shows Curie-Weiss paramagnetism above 100K with an experimental magnetic moment of 2.56(2)_B/Ce atom. With samarium as rare earth metal component the silicide SmIr_0.266(8)Si_1.734(8) with -ThSi₂ type structure was obtained: I4₁/amd, a=409.3(1), c=1397.2(5)pm, wR2=0.0575, 161F² values, and 9 variable parameters. Within the three-dimensional [Ir_0.266Si_1.734] network the Ir/Si–Ir/Si distances range from 230 to 237pm.     

Platinum–germanium ordering in UPtGe

The non-centrosymmetric structure of UPtGe was investigated by X-ray diffraction on both powders and single crystals: EuAuGe type, Imm2, a=432.86(5), b=718.81(8), c=751.66(9) pm, wR₂=0.0738 for 399 F² values and 22 variables. The platinum and germanium atoms form two-dimensional layers of puckered Pt₃Ge₃ hexagons with short PtGe intralayer distances of 252 and 253 pm. These condensed two-dimensionally infinite nets are interconnected to each other via weak PtPt contacts with bond distances of 300 pm. The two crystallographically independent uranium atoms are situated above and below the six-membered platinum–germanium rings. The U1 atoms have six closer germanium neighbors while the U2 atoms have six closer platinum neighbors. The group–subgroup relation with the KHg₂ type structure is presented.     

New Rare‐Earth Metal Germanides RE2Ge9 (RE = Nd,Sm) by Thermal Decomposition of High‐Pressure Phases REGe5

The rare‐earth metal germanides RE₂Ge₉ (RE = Nd, Sm) have been prepared by thermal decomposition of the metastable high‐pressure phases REGe₅ at ambient pressure. The compounds adopt an orthorhombic unit cell with a = 396.34(4) pm; b = 954.05(8) pm and c = 1238.4(1) pm for Nd₂Ge₉ and a = 395.46(7) pm; b = 946.4(2) pm and c = 1232.1(3) pm for Sm₂Ge₉. Crystal structure refinements reveal space group Pmmn (No. 59) for Nd₂Ge₉. The atomic pattern resembles an ordered defect variety of the pentagermanide motif REGe₅ (RE = La; Nd, Sm, Gd, Tb) comprising corrugated germanium layers. These condense into a three‐dimensional network interconnected by eight‐coordinated germanium atoms. The resulting framework channels along [100] enclose the neodymium atoms. With respect to the atomic arrangement of the pentagermanides, half of the interlayer germanium atoms are eliminated in an ordered way so that occupied and empty germanium columns alternate along [001]. The rare‐earth metal atoms of both types of compounds, REGe₅ and RE₂Ge₉, exhibit the electronic states 4f ³ and 4f ⁵ (oxidation state +3) for neodymium and samarium, respectively, evidencing that the modification of the germanium network leaves the electron configuration of the metal atoms unaffected.     

Die Kristallstruktur von Ge5O[PO4]6

Zusammenfassung Die Kristallstruktur der Verbindung Ge₅O[PO₄]₆ wurde auf Grund dreidimensionaler Einkristalldaten ausWeissenberg-Aufnahmen ermittelt und nach der Methode der kleinsten Quadrate verfeinert: Raumgruppe ;a=7,994±0,004 undc=24,87±0,01 Å;Z=3; 467 unabhängige Reflexe;R=0,086.Die Kristallstruktur wird aus singulären [GeO₆]-Oktaedern und [Ge₂O₇]-Doppeltetraedern aufgebaut, die über [PO₄]-Tetraeder zu einem dreidimensionalen Strukturverband vernetzt sind. Die mittleren Abstände betragen: Ge^[6]–O=1,863, Ge^[4]–O=1,704 und P–O=1,525 Å.

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The crystal structure of Ge₅O[PO₄]₆

The crystal structure of Ge₅O[PO₄]₆ has been determined and refined by least-squares, using three-dimensional x-ray data fromWeissenberg-photographs: space group ;a=7.994±0.004 andc=24.87±0.01 Å;Z=3; 467 independent reflections;R=0.086.The crystal structure consists of isolated [GeO₆] octahedra and [Ge₂O₇] double tetrahedra which are linked by [PO₄] groups forming a three-dimensional network. The average interatomic distances are: Ge^[6]–O=1.863, Ge^[4]–O=1.704 and P–O=1.525 Å.

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Mit 2 Abbildungen     

Two‐ and Three‐Dimensional [IrSi] Networks in the Silicides Sm3Ir2Si2, HoIrSi,and YbIrSi

New intermetallic rare earth iridium silicides Sm₃Ir₂Si₂, HoIrSi, and YbIrSi were synthesized by reaction of the elements in sealed tantalum tubes in a high‐frequency furnace. The compounds were investigated by X‐ray diffraction both on powders and single crystals. HoIrSi and YbIrSi crystallize in a TiNiSi type structure, space group Pnma: a = 677.1(1), b = 417.37(6), c = 745.1(1) pm, wR2 = 0.0930, 340 F² values for HoIrSi, and a = 667.2(2), b = 414.16(8), c = 742.8(2) pm, wR2 = 0.0370, 262 F² values for YbIrSi with 20 parameters for each refinement. The iridium and silicon atoms build a three‐dimensional [IrSi] network in which the holmium(ytterbium) atoms are located in distorted hexagonal channels. Short Ir–Si distances (246–256 pm in YbIrSi) are indicative for strong Ir–Si bonding. Sm₃Ir₂Si₂ crystallizes in a site occupancy variant of the W₃CoB₃ type: Cmcm, a = 409.69(2), b = 1059.32(7), c = 1327.53(8) pm, wR2 = 0.0995, 383 F² values and 27 variables. The Ir1, Ir2, and Si atoms occupy the Co, B2, and B1 positions of W₃CoB₃, leading to eight‐membered Ir₄Si₄ rings within the puckered two‐dimensional [IrSi] network. The Ir–Si distances range from 245 to 251 pm. The [IrSi] networks are separated by the samarium atoms. Chemical bonding in HoIrSi, YbIrSi, and Sm₃Ir₂Si₂ is briefly discussed.     

Single Crystal Growth, Crystal Structure and Thermal Behaviour of Mercury(II) Pyrophosphate Dihydrate

Colourless single crystals of Hg₂P₂O₇(H₂O)₂ up to 0.4 mm in length were grown by a diffusion technique starting from aqueous solutions of Na₄P₂O₇ and Hg(NO₃)₂. The crystal structure is isotypic with that of Ca₂P₂O₇(H₂O)₂ and was determined from a four-circle diffractometer data set (space group , Z=2, a=6.9374(7), b=7.4396(8), c=7.9863(7)Å, =84.685(8), =75.158(8), =72.818(8)°, 2413 structure factors, 132 parameters, R[F ²>2(F ²)]=0.0181, wR(F ² all)= 0.0384). Hg₂P₂O₇(H₂O)₂ is composed of approximately eclipsed P₂O₇ ^4– anions and distorted [HgO₆] octahedra and [HgO₇] pentagonal bipyramids as the main building units. The structure is stabilized by inter-water hydrogen bonding and by hydrogen bonding between terminal pyrophosphate oxygen atoms and the water molecules. The P–O distances to the terminal oxygen atoms range from 1.501(4) to 1.536(3)Å, with an average of 1.522Å; the mean distance of 1.615Å to the bridging O atom is considerably longer with an (O–P–O) bridging angle of 123.44(19)°. Both Hg atoms have two short Hg–O bonds around 2.17Å and additional bonds ranging from 2.381(3) to 2.708(4)Å. Upon heating above 160°C, both crystal water molecules are released simultaneously and anhydrous Hg₂P₂O₇ is formed which is stable up to ca. 660°C. Above this temperature the material decomposes completely.     

Zr 5Ir 2In 4 – A Superstructure of the Lu 5Ni 2In 4 Type

Zr₅Ir₂In₄ was synthesized by reaction of the elements in a glassy carbon crucible in a water-cooled sample chamber of an induction furnace. The sample was characterized by X-ray diffraction on both powder and single crystals. Zr₅Ir₂In₄ crystallizes with a pronounced Lu₅Ni₂In₄ type subcell, space group Pbam, a=1739.5(6), b=766.3(2), c=338.9(2) pm. Weak additional reflections force a doubling of the subcell c axis. The superstructure of Zr₅Ir₂In₄ is of a new type: Pnma, a=1739.5(6), b=677.8(2), c=766.3(2) pm, wR2=0.0529, 1592 F² values, and 60 variable parameters. The group-subgroup scheme for the klassengleiche symmetry reduction is presented. The formation of the superstructure is most likely due to a puckering effect (size of the iridium atoms). The crystal chemistry of Zr₅Ir₂In₄ is briefly discussed.     

Solvothermal Synthesis,Crystal Structure,and Properties of the First Zinc Containing Thioantimonate(III) [Zn(<Emphasis Type="Italic">tren</Emphasis>)]<Subscript>2</Subscript>Sb<Subscript>4</Subscript>S<Subscript>8</Subscript>·0.75 H<Subscript>2</Subscript>O

Summary. Yellow crystals of the title compound were obtained under solvothermal conditions reacting elemental Zn, Sb, and S in a solution of tris(2-aminoethyl)amine (=tren) and water. The compound crystallises in the monoclinic space group P2₁/c with a=13.0247(7), b=22.308(2), c=12.1776(6) Å, and =105.352(6)°. In the structure of [Zn(tren)]₂Sb₄S₈·0.75 H₂O two [Zn(tren)]²⁺ cations are bound to the [Sb₄S₈]^4– anion via S atoms. The Zn²⁺ ions are in a trigonal bipyramidal environment of four N atoms of the tetradentate tren ligand and one S atom of the [Sb₄S₈]^4– anion. The anion is formed by SbS₃ and SbS₄ units which share common corners and edges. The interconnection mode yields three different non-planar Sb₂S₂ heterorings. The shortest intermolecular Sb–S distance amounts to about 3.7Å, and taking this long separation into account undulated chains running along [001] are formed with the water molecules residing in the pocket-like cavities. Upon heating the compound decomposes in one step starting at about 240°C. The final decomposition product was identified as ZnS and Sb₂S₃ by X-ray powder diffractometry. Additionally, spectroscopic data as well as synthetic procedures for [Zn(tren)]₂Sb₄S₈·0.75 H₂O are reported.     

The Rare Earth Metal-Rich Indides <Emphasis Type="Italic">RE</Emphasis><Subscript>4</Subscript>RhIn (<Emphasis Type="Italic">RE</Emphasis> = Gd–Tm,Lu)

Summary. The rare earth-transition metal-indides RE ₄RhIn (RE = Gd–Tm, Lu) were prepared by arc-melting of the elements and subsequent annealing. Single crystals were grown via slowly cooling of the samples. The indides were investigated via X-ray powder diffraction and several structures were refined from X-ray single crystal diffractometer data: , a = 1370.7(9) pm, wR2 = 0.049, 428 F ² values for Gd₄RhIn, a = 1360.3(6) pm, wR2 = 0.028, 420 F ² values for Tb₄RhIn, a = 1354.5(2) pm, wR2 = 0.041, 380 F ² values for Dy₄RhIn, a = 1349.2(3) pm, wR2 = 0.029, 410 F ² values for Ho₄RhIn, a = 1342.5(5) pm, wR2 = 0.037, 403 F ² values for Er₄RhIn, a = 1337.8(3) pm, wR2 = 0.038, 394 F ² values for Tm₄RhIn with 14 variable parameters per refinement, and a = 1329.7(3) pm for Lu₄RhIn. In this new structure type, the rhodium atoms have a trigonal prismatic rare earth coordination. Condensation of the RhRE ₆ prisms leads to a three-dimensional network which leaves voids that are filled by regular In₄ tetrahedra (317 pm In–In distance) in Gd₄RhIn. The indium atoms have twelve nearest neighbors (3 In + 9 RE) in icosahedral coordination. The gadolinium atoms build up a three-dimensional, adamantane-like network of condensed, face-sharing empty octahedra.     

Bridgman crystal growth of Yb2Ru3Ge4—A ternary germanide with a three-dimensional network of condensed distorted RuGe5 and RuGe6 units

The germanide Yb₂Ru₃Ge₄ was synthesized from the elements using the Bridgman crystal growth technique. The monoclinic Hf₂Ru₃Si₄ type structure was investigated by X-ray powder and single crystal diffraction: C2/c, Z=8, a=1993.0(3) pm, b=550.69(8) pm, c=1388.0(2) pm, β=128.383(9)°, wR₂=0.0569, 2047 F² values, and 84 variables. Yb₂Ru₃Ge₄ contains two crystallographically independent ytterbium sites with coordination numbers of 18 and 17 for Yb1 and Yb2, respectively. Each ytterbium atom has three ytterbium neighbors at Yb-Yb distances ranging from 345 to 368 pm. The shortest interatomic distances occur for the Ru-Ge contacts. The three crystallographically independent ruthenium sites have between five and six germanium neighbors in distorted trigonal bipyramidal (Ru1Ge₅) or octahedral (Ru2Ge₆ and Ru3Ge₆) coordination at Ru-Ge distances ranging from 245 to 279 pm. The Ru2 atoms form zig-zag chains running parallel to the b-axis at Ru2-Ru2 of 284 pm. The RuGe₅ and RuGe₆ units are condensed via common edges and faces leading to a complex three-dimensional [Ru₃Ge₄] network.     

Novel Immobilized Hydrosilylation Catalysts Based on Rhodium 1,3-Bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidenes

Summary. The reactivity of a well defined Rh (I) complex, i.e. Rh(CF₃COO)(NHC)(COD) (1, NHC=1,3-bis(2,4,6-trimethylphenyl)-3,4,5,6-tetrahydropyrimidin-2-ylidene, COD=⁴-cycloocta-1,5-diene) in the hydrosilylation of 1-alkenes, alkynes, and ,-unsaturated carbonyl compounds, respectively, is described. With this complex, excellent reactivity was observed and turn-over numbers (TONs) up to 1000 were reached. A supported version of 1 was realized by reaction of RhCl(NHC)(COD) with PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COOAg (PS-DVB=poly(styrene-co-divinylbenzene) to yield PS-DVB–CH₂–O–CO–CF₂–CF₂–CF₂–COORh(NHC)(COD). This supported version of 1 exhibited at least comparable, in some cases increased reactivity compared to 1 and allowed the rapid removal of the catalyst from the reaction mixture. Due to reduced catalyst bleeding, the synthesis of target compounds with a Rh-content of less than 130ppm was accomplished.This revised version was published online in February 2005. In the previous version the issue was not marked as a special issue, and the issue title and the editor was missing     

Tetramethylammonium-calcium-triazid. Darstellung und Kristallstruktur

[N(CH₃)₄]Ca(N₃)₃,M=240.29, was prepared from aqueous solutions of tetramethylammoniumazide with calciumazide at 298 K. The crystals are tetragonala=936.6(7) pm,c=694.7(5)pm, space group P4/nmm,Z=2, (x)=1.31Mgm^–3. The crystal structure was determined by single crystal x-ray diffraction (234 Mo-K-reflections, =0.469 mm^–1,R=0.064). Calcium is octahedrally coordinated to six azide groups. The octahedra are connected via azide groups to a threedimensional array with the complex ammonium ions between. The terminal nitrogen atoms of the azide groups and the methyl groups are considerably disordered.

     

Solvothermal Synthesis, Crystal Structure, and Properties of the First Zinc Containing Thioantimonate(III) [Zn( tren)] 2Sb 4S 8·0.75 H 2O

Yellow crystals of the title compound were obtained under solvothermal conditions reacting elemental Zn, Sb, and S in a solution of tris(2-aminoethyl)amine (=tren) and water. The compound crystallises in the monoclinic space group P2₁/c with a=13.0247(7), b=22.308(2), c=12.1776(6) Å, and =105.352(6)°. In the structure of [Zn(tren)]₂Sb₄S₈·0.75 H₂O two [Zn(tren)]²⁺ cations are bound to the [Sb₄S₈]^4– anion via S atoms. The Zn²⁺ ions are in a trigonal bipyramidal environment of four N atoms of the tetradentate tren ligand and one S atom of the [Sb₄S₈]^4– anion. The anion is formed by SbS₃ and SbS₄ units which share common corners and edges. The interconnection mode yields three different non-planar Sb₂S₂ heterorings. The shortest intermolecular Sb–S distance amounts to about 3.7Å, and taking this long separation into account undulated chains running along [001] are formed with the water molecules residing in the pocket-like cavities. Upon heating the compound decomposes in one step starting at about 240°C. The final decomposition product was identified as ZnS and Sb₂S₃ by X-ray powder diffractometry. Additionally, spectroscopic data as well as synthetic procedures for [Zn(tren)]₂Sb₄S₈·0.75 H₂O are reported.     

The Crystal Structures of Eu5Ge3 and EuIrGe2

Eu₅Ge₃ and EuIrGe₂ were prepared from the elements in tantalum tubes, and their crystal structures were determined from single crystal X-ray data. Eu₅Ge₃ adopts the structure of Cr₅B₃: I4/mcm, a = 799.0(1)pm, c = 1 536.7(1)pm, Z = 4, wR2 = 0.0421 for 669 F² values and 16 variables. The structure of Eu₅Ge₃ contains isolated germanium atoms and germanium atom pairs with a Ge? Ge distance of 256.0 pm. Eu₅Ge₃ may be described as a Zintl phase with the formulation [5 Eu²⁺]¹⁰⁺[Ge]^4?[Ge₂]^6?. Magnetic investigations of Eu₅Ge₃ show Curie-Weiss behaviour above 50 K with a magnetic moment of μ_exp = 7.6(1) μ_B which is close to the free ion value of μ_eff = 7.94 μ_B for Eu²⁺. EuIrGe₂ is isotypic with CeNiSi₂: Cmcm, a = 445.5(2) pm, b = 1 737.4(4) pm, c = 426.6(1) pm, Z = 4, wR2 = 0.0507 for 295 F² values and 18 variables. The structure of EuIrGe₂ is an intergrowth of ThCr₂Si₂-like slabs with composition EuIr₂Ge₂ and AlB₂-like slabs with composition EuGe₂ in an AB stacking sequence. Both slabs are distorted when compared to the symmetry of the prototypes. The Ge? Ge distance of 256.6 pm in the AlB₂-like fragment is comparable to that in Eu₅Ge₃.     

Thermal,Magnetic, Electronic,and Superconducting Properties of Rare‐Earth Metal Pentagermanides REGe5 (RE = La,Nd, Sm,Gd) and Synthesis of TbGe5

A series of isotypic rare‐earth metal pentagermanides including the new compound TbGe₅ were prepared by high‐pressure synthesis. They crystallize in the orthorhombic space group Immm [No. 71; a = 395.70(9) pm; b = 611.1(2) pm, and c = 983.6(3) pm for TbGe₅]. The crystal structure is isotypic to LaGe₅ and consists of puckered germanium slabs, which sandwich a second germanium species and the rare‐earth metal atoms. At ambient pressure, the thermal decomposition of the phases REGe₅ (RE = La, Nd, Sm, Gd, and Tb) proceeds via discrete intermediate steps into Ge(cF8) and thermodynamically stable germanium‐poorer phases. The investigated compounds REGe₅ are paramagnetic metallic conductors, which order antiferromagnetically at low temperatures. Specific heat measurements reveal that the superconducting state of LaGe₅ below T_c = 7.1(1) K is characterized by a critical field of μ₀H_c2 = 0.2 T and weak electron‐phonon coupling. Density‐functional based band‐structure calculations yield a very similar electronic structure for all the isotypic REGe₅ compounds. Besides a slight increase in the width of the valence band for smaller RE atoms, only minor differences are found for the two different germanium environments.     

In-Situ Separation and Determination of Palladium from Platinum Based on Different Vaporization Temperatures by Electrothermal Vaporization Inductively Coupled Plasma Optical Emission Spectrometry with YPA4 Resin Acting Both as Adsorption Material and Chemical Modifier

A new method has been developed for in-situ separation of Pd from a Pt matrix and determination of trace Pd based on different vaporization temperatures by electrothermal vaporization (ETV) inductively coupled plasma optical emission spectrometry (ICP-OES) with the use of polythioether backbone modified with a diaminoisopropylmercaptane chelating group (YPA₄), both as solid phase extractant and chemical modifier. In 0.5M HNO₃, Pd and Pt can be adsorbed by YPA₄. The resin loaded with Pd and Pt was then prepared to form a slurry that can be directly introduced into the graphite furnace without any pretreatment. The factors affecting in-situ separation of Pd from the Pt matrix were investigated in detail. It was found that, in the presence of YPA₄, Pd could be quantitatively vaporized at lower vaporization temperatures (1800°C–1900°C), while Pt could not be vaporized from the graphite furnace at the same temperature, its quantitative vaporization temperature being 2600°C. Based on the different vaporization temperatures, in-situ separation of Pd from the Pt matrix and determination of trace Pd by ETV-ICP-OES was achieved in the temperature range of 1800°C–1900°C. Under the optimized conditions, the detection limit (3) of Pd is 60pg, and the relative standard deviation (RSD) is 5.6% (n=9, C=0.2µgmL^–1). The method has been applied to the determination of trace Pd in anode slime and Auto Catalyst NIST SRM 2557 reference material, and the determined values coincide with the certified values.