Neue Germanide mit geordneter Ce3Pt4Ge6‐Struktur – Die Verbindungen Ln3Pt4Ge6 (Ln: Pr–Dy)

New Germanides with an Ordered Variant of the Ce₃Pt₄Ge₆ Type of Structure – The Compounds Ln₃Pt₄Ge₆ (Ln: Pr–Dy) Six new germanides Ln₃Pt₄Ge₆ with Ln = Pr–Dy were synthesized by heating mixtures of the elements at 900 °C, annealing the inhomogeneous powders at 1050‐1100 °C for six days and then cooling down from 700 °C in the course of two months. The crystal structures of Pr₃Pt₄Ge₆ (a = 26.131(5), b = 4.399(1), c = 8.820(2) Å), Sm₃Pt₄Ge₆ (a = 25.974(3), b = 4.356(1), c = 8.748(1) Å), and Dy₃Pt₄Ge₆ (a = 26.079(5), b = 4.311(1), c = 8.729(2) Å) were determined by single crystal X‐ray methods. The compounds are isotypic (Pnma, Z = 4) and crystallize with an ordered variant of the Ce₃Pt₄Ge₆ type of structure (Cmcm, Z = 2) consisting of CaBe₂Ge₂‐ and YIrGe₂‐analogous units. The platinum atoms are located in distorted square pyramids of germanium atoms and build up with them a three‐dimensional network. The coordination polyhedra of the platinum and germanium atoms around the rare‐earth metal atoms are pentagonal and hexagonal prisms. These are completed by some additional atoms resulting in coordination numbers of 14 and 15 respectively. The other germanides were investigated by powder methods resulting in the following lattice constants: a = 26.067(6), b = 4.388(1), c = 8.800(2) Å for Ln = Nd; a = 25.955(7), b = 4.337(1), c = 8.728(2) Å for Ln = Gd; a = 25.944(5), b = 4.322(1), c = 8.698(2) Å for Ln = Tb. The atomic arrangement of Ln₃Pt₄Ge₆ is compared with the well‐known monoclinic structure of Y₃Pt₄Ge₆.     

Preparation and Crystal Structure of Rare Earth Rhenates: the Series Ln5Re2O12 with Ln = Y,Gd–Lu,and the Praseodymium Rhenates Pr3ReO8, Pr3Re2O10, and Pr4Re2O11

The crystal structure of the known compounds Ln₅Re₂O₁₂ (Ln = Y, Gd, Dy–Lu) and the new isotypic terbium rhenate Tb₅Re₂O₁₂ was determined from X‐ray data of a twinned crystal of Ho₅Re₂O₁₂: B2/m, a = 1236.5(4) pm, b = 748.2(2) pm, c = 563.8(1) pm, γ = 107.73(3)°, Z = 2, R = 0.034 for 379 structure factors and 37 variable parameters. The rhenium atoms (oxidation number +4.5) have octahedral oxygen coordination. These ReO₆ octahedra share edges, thus forming infinite strings with alternating short and long Re–Re distances: 243.6(2) and 320.1(2) pm. Of the three holmium positions two are surrounded by seven oxygen atoms and the third one has octahedral oxygen coordination. The crystal structure of Pr₃ReO₈ was refined from single‐crystal X‐ray data: P2₁/a, a = 1498.0(2) pm, b = 749.09(8) pm, c = 610.48(9) pm, γ = 110.39(1)°, R = 0.017 for 2082 F values and 110 variable parameters. It is isotypic with a structure first determined for Sm₃ReO₈. The new compounds Pr₃Re₂O₁₀ and Pr₄Re₂O₁₁ were prepared by reaction of elemental praseodymium with the metaperrhenate Pr(ReO₄)₃. They were characterized through their X‐ray powder diagrams. Pr₃Re₂O₁₀ was found to be monoclinic: a = 778.47(9) pm, b = 773.62(9) pm, c = 706.10(8) pm, β = 114.77(1)°. It is isotypic with La₃Os₂O₁₀ and La₃Re₂O₁₀. Pr₄Re₂O₁₁ crystallizes with Nd₄Re₂O₁₁ type structure with the tetragonal lattice constants a = 1272.49(3) pm, c = 562.29(2) pm. The compounds Nd₄Re₂O₁₁ and Sm₄Re₂O₁₁ are confirmed. The magnetic properties of Ho₅Re₂O₁₂, Tb₅Re₂O₁₂, Pr₃Re₂O₁₀, Pr₄Re₂O₁₁, Nd₄Re₂O₁₁, and Sm₄Re₂O₁₁ were investigated with a Faraday balance. None of these compounds shows magnetic order above 200 K.     

Synthese und Struktur der Nitridoborat‐Nitride Ln4(B2N4)N (Ln = La,Ce) des Formeltyps Ln3+x(B2N4)Nx (x = 0, 1, 2)

Synthesis and Structure of Nitridoborate Nitrides Ln₄(B₂N₄)N (Ln = La, Ce) of the Formula Type Ln_3+x(B₂N₄)N_x (x = 0, 1, 2) The missing member of the formula type Ln_3+x(B₂N₄)N_x with x = 1 was synthesized and characterized for Ln = La and Ce. According to the single‐crystal X‐ray structure solution Ce₄(B₂N₄)N crystallizes in the space group C2/m (Z = 2) with the lattice parameters a = 1238.2(1) pm, b = 357.32(3) pm, c = 905.21(7) pm and β = 129.700(1)°. The anisotropic structure refinement converged at R1 = 0.039 and wR2 = 0.099 for all independent reflections. A powder pattern of La₄(B₂N₄)N was indexed isotypically with a = 1260.4(1) pm, b = 366.15(3) pm, c = 919.8(1) pm and β = 129.727(6)°. A structure rational for nitridoborates and nitridoborate nitrides containing B₂N₄ ions with the general formula Ln_3+x(B₂N₄)N_x with x = 0, 1, 2 is presented.     

Semiconducting La2AuP3, the Metallic Conductor Ce2AuP3, and other Rare‐Earth Gold Phosphides Ln2AuP3 with Two Closely Related Crystal Structures

The compounds Ln₂AuP₃ were synthesized by reaction of the elemental components in evacuated silica tubes. Their crystal structures were determined from single‐crystal diffractometer data. The compounds with Ln = La, Ce, and Pr crystallize with an orthorhombic U₂NiC₃ type structure (Pnma, Z = 4). The structure refinement for Ce₂AuP₃ resulted in a = 774.14(6) pm, b = 421.11(4) pm, c = 1612.3(1) pm, R = 0.019 for 1410 structure factors and 38 variable parameters. For Pr₂AuP₃ a residual of R = 0.024 was obtained. Nd₂AuP₃ crystallizes with a monoclinic distortion of this structure: P2₁/c, Z = 4, a = 416.14(4) pm, b = 768.87(6) pm, c = 1647.1(2) pm, β = 104.06(1)°, R = 0.022 for 1361 F values and 56 variables. The near‐neighbor coordinations of the two structures are nearly the same. In both structures the gold and phosphorus atoms form two‐dimensionally infinite nets, where the gold atoms are tetrahedrally coordinated by phosphorus atoms with Au–P distances varying between 245.8 and 284.2 pm. Two thirds of the phosphorus atoms form pairs with single‐bond distances varying between 217.7 and 218.9 pm. Thus, using oxidation numbers the structures can be rationalized with the formulas (Ln⁺³)₂[AuP₃]^–6 and (Ln⁺³)₂Au⁺¹(P₂)^–4P^–3. Accordingly, La₂AuP₃ is a diamagnetic semiconductor. Pr₂AuP₃ is semiconducting with an antiferromagnetic ground state, showing metamagnetism with a critical field of B_c = 0.5(± 0.1) T. In contrast, the cerium compound is a metallic conductor, even though its cell volume indicates that the cerium atoms are essentially trivalent, as is also suggested by the ferro‐ or ferrimagnetic behavior of the compound.     

Ternary Indides RE4Pd10In21 (RE = La,Ce, Pr,Nd, Sm) — Synthesis,Structure, and Physical Properties

The ternary indium compounds RE₄Pd₁₀In₂₁ (RE = La, Ce, Pr, Nd, Sm) were synthesized from the elements in glassy carbon crucibles in a high‐frequency furnace. Single crystals of Sm₄Pd₁₀In₂₁ were obtained from an indium flux. An arc‐melted precursor alloy of the starting composition ～SmPd₃In₆ was annealed with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. All compounds were investigated by X‐ray powder diffraction and the structures were refined from single crystal diffractometer data. The RE₄Pd₁₀In₂₁ indides are isotypic with Ho₄Ni₁₀Ga₂₁, space group C2/m: a = 2314.3(2), b = 454.70(7), c = 1940.7(2) pm, β = 133.43(2)°, wR2 = 0.0681, 1678 F² values for La₄Pd₁₀In₂₁, a = 2308.2(1), b = 452.52(4), c = 1944.80(9) pm, β = 133.40(1)°, wR2 = 0.0659, 1684 F² values for Ce₄Pd₁₀In₂₁, a = 2303.8(2), b = 450.78(4), c = 1940.6(1) pm, β = 133.39(1)°, wR2 = 0.0513, 1648 F² values for Pr₄Pd₁₀In₂₁, a = 2300.2(2), b = 449.75(6), c = 1937.8(2) pm, β = 133.32(1)°, wR2 = 0.1086, 1506 F² values for Nd₄Pd₁₀In₂₁, and a = 2295.6(2), b = 447.07(4), c = 1935.7(1) pm, β = 133.16(1)°, wR2 = 0.2291, 2350 F² values for Sm₄Pd₁₀In₂₁, with 108 variables per refinement. All palladium atoms have a trigonal prismatic coordination. The strongest bonding interactions occur for the Pd—In and In—In contacts. The structures are composed of covalently bonded three‐dimensional [Pd₁₀In₂₁] networks in which the rare earth metal atoms fill distorted pentagonal channels. The crystal chemistry and chemical bonding in these indides is briefly discussed. Magnetic susceptibility measurements show diamagnetism for La₄Pd₁₀In₂₁ and Curie‐Weiss paramagnetism for Ce₄Pd₁₀In₂₁, Pr₄Pd₁₀In₂₁, and Nd₄Pd₁₀In₂₁. The neodymium compound orders antiferromagnetically at T_N = 4.5(2) K and undergoes a metamagnetic transition at a critical field of 1.5(2) T. All the RE₄Pd₁₀In₂₁ indides studied are metallic conductors.     

Synthese und Kristallstrukturen von Bromid—Thiosilicaten Ln3Br[SiS4]2 der Lanthanide (Ln = La,Ce, Pr,Nd, Sm,Gd)

Synthesis and Crystal Structures of Lanthanide Bromide Thiosilicates Ln₃Br[SiS₄]₂ (Ln = La, Ce, Pr, Nd, Sm, Gd) Single crystals of the bromide—thiosilicates Ln₃Br[SiS₄]₂ were prepared by reaction of lanthanide metal (Ln = La, Ce, Pr, Nd, Sm, Gd), sulfur, silicon and bromine in quartz glass tubes. The thiosilicates crystallize in the monoclinic spacegroup C2/c (Z = 4) isotypically to the iodide analogues Ln₃I(SiS₄)₂ and the A—type chloride—oxosilicates Ln₃Cl[SiO₄]₂ with the following lattice constants: La₃Br[SiS₄]₂: a = 1583.3(4) pm, b = 783.0(1) pm, c = 1098.2(3) pm, β = 97.33(3)° Ce₃Br[SiS₄]₂: a = 1570.4(3) pm, b = 776.5(2) pm, c = 1092.2(2) pm, β = 97.28(2)° Pr₃Br[SiS₄]₂: a = 1562.6(3) pm, b = 770.1(2) pm, c = 1088.9(2) pm, β = 97.50(2)° Nd₃Br[SiS₄]₂: a = 1561.4(4) pm, b = 766.0(1) pm, c = 1085.3(2) pm, β = 97.66(3)° Sm₃Br[SiS₄]₂: a = 1555.4(3) pm, b = 758.5(2) pm, c = 1079.9(2) pm, β = 98.28(2)° Gd₃Br[SiS₄]₂: a = 1556.5(3) pm, b = 750.8(1) pm, c = 1074.5(2) pm, β = 99.26(2)° In the crystal structures the bromide ions form chains along [001] with trigonal planar coordination by lanthanide cations, while the [SiS₄]^4‐—building units display isolated distorted tetrahedra.     

Syntheses and Structures of RE4Pt10In21 (RE = La–Nd)

The isotypic indides RE₄Pt₁₀In₂₁ (RE = La, Ce, Pr, Nd) were prepared by melting mixtures of the elements in an arc‐furnace under an argon atmosphere. Single crystals were synthesized in tantalum ampoules using special temperature modes. The four samples were studied by powder and single crystal X‐ray diffraction: Ho₄Ni₁₀Ga₂₁ type, C2/m, a = 2305.8(2), b = 451.27(4), c = 1944.9(2) pm, β = 133.18(7)°, wR2 = 0.045, 2817 F² values, 107 variables for La₄Pt₁₀In₂₁, a = 2301.0(2), b = 448.76(4), c = 1941.6(2) pm, β = 133.050(8)°, wR2 = 0.056, 3099 F² values, 107 variables for Ce₄Pt₁₀In₂₁, a = 2297.4(2), b = 447.4(4), c = 1939.7(2) pm, β = 132.95(1)°, wR2 = 0.059, 3107 F² values, 107 variables for Pr₄Pt₁₀In₂₁, and a = 2294.7(4), b = 446.1(1), c = 1938.7(3) pm, β = 132.883(9)°, wR2 = 0.067, 2775 F² values, 107 variables for Nd₄Pt₁₀In₂₁. The 8j In2 positions of all structures have been refined with a split model. The In1 sites of the lanthanum and the cerium compound show small defects, leading to the refined composition La₄Pt₁₀In_20.966(6) and Ce₄Pt₁₀In_20.909(6) for the investigated crystals. The same position shows Pt/In mixing in the praseodymium and neodymium compound leading to the refined compositions Pr₄Pt_10.084(9)In_20.916(9) and Nd₄Pt_10.050(9)In_20.950(9). All platinum atoms have a tricapped trigonal prismatic coordination by rare‐earth metal and indium atoms. The shortest interatomic distances occur for Pt–In followed by In–In. Together, the platinum and indium atoms build up three‐dimensional [Pt₁₀In₂₁] networks in which the rare earth atoms fill distorted pentagonal tubes. The crystal chemistry of RE₄Pt₁₀In₂₁ is discussed and compared with the RE₄Pd₁₀In₂₁ indides and isotypic gallides.     

Ca2Pd2In and Ca2Pt2In with Monoclinic HT‐Pr2Co2Al Type Structure

The metal‐rich indides Ca₂Pd₂In and Ca₂Pt₂In were synthesised from the elements in sealed tantalum ampoules in an induction furnace. Both samples were investigated by X‐ray powder and single crystal diffraction: HT‐Pr₂Co₂Al type, C2/c, a = 1017.6(5), b = 574.1(3), c = 812.7(3) pm, β = 104.54(2)°, wR2 = 0.0344, 590 F² values for Ca₂Pd₂In and a = 1004.3(3), b = 568.9(1), c = 813.1(2) pm, β = 104.25(2)°, wR2 = 0.0435, 654 F² values for Ca₂Pt₂In with 25 variables per refinement. The structure contain Pd₂ (272 pm) and Pt₂ (264 pm) dumb‐bells with a trigonal prismatic coordination for each transition metal atom. These AlB₂ related slabs are condensed via common edges. Together the palladium and indium atoms build up three‐dimensional [Pd₂In] and [Pt₂In] polyanionic networks in which the calcium atoms fill larger channels. The bonding of calcium to the network proceeds via shorter Ca–Pd and Ca–Pt contacts. Ca₂Pd₂In and Ca₂Pt₂In are Pauli paramagnets.     

Darstellung und Kristallstruktur der bekannten Zintl‐Phasen Cs3Sb7 und Cs4Sb2

Synthesis and Crystal Structure of the known Zintl Phases Cs₃Sb₇ and Cs₄Sb₂ Cs₃Sb₇ and Cs₄Sb₂ were synthesized from the elements and their crystal structures were determined on the basis of single crystal x‐ray data. Cs₃Sb₇ crystallizes in the monoclinic system with space group P2₁/c (a = 1605.7(1) pm, b = 1571.1(1) pm, c = 2793.9(2) pm, β = 96.300(2)°, Z = 16) and contains anions Sb₇^3–. In the structure of Cs₄Sb₂ (orthorhombic, space group Pnma, a = 1598.5(3) pm, b = 631.9(2) pm, c = 1099.5(2) pm, Z = 4) dumbbells Sb₂^4– are present.     

Ternary Transition Metal Antimonides T5T' 1‐xSb2+x (T = Ti,Zr, Hf; T' = Fe,Co, Ni,Cu, Ru,Rh, Pd,Cd) with Nb5SiSn2 (Ordered W5Si3, Filled V4SiSb2) Type Structure

Fifteen new ternary antimonides T₅T' _1‐xSb_2+x were synthesized by reaction of the elemental components in an arc‐melting furnace. They crystallize with a tetragonal structure first reported for Nb₅SiSn₂ (space group I4/mcm, Z = 4.) A structure refinement from four‐circle X‐ray diffractometer data of Hf₅Fe_1‐xSb_2+x (a = 1086.0(1) pm, c = 550.1(1) pm, R = 0.033 for 270 structure factors and 18 variable parameters) showed deviations from the ideal occupancy for two atomic sites, resulting in the composition Hf_4.929(3)Fe_0.67(1)Sb_2.33(1). Structure refinements from X‐ray powder data resulted in the formula Ti₅Ni_0.45(2)Sb_2.55(2), while no deviation from the ideal composition was observed for Ti₅RhSb₂. The crystal structures of these compounds are discussed together with those of related binary and ternary compounds.     

Crystal Structure and Properties of Some Filled and Unfilled Skutterudites: GdFe4P12, SmFe4P12, NdFe4As12, Eu0.54Co4Sb12, Fe0.5Ni0.5P3, CoP3, and NiP3

The new cubic compound Fe_0.5Ni_0.5P₃ (a = 775.29(5) pm) as well as the known compounds CoP₃ and NiP₃ were synthesized from the elemental components using tin as a flux. Their skutterudite (CoAs₃) type structures were refined from single‐crystal X‐ray data. The new compound GdFe₄P₁₂ was prepared by reaction of an alloy Gd_1/3Fe_2/3 with phosphorus in a tin flux. Its cubic “filled” skutterudite (LaFe₄P₁₂ type) structure was refined from single‐crystal X‐ray data: a = 779.49(4) pm, R = 0.019 for 304 structure factors and 11 variable parameters. SmFe₄P₁₂ shows Van Vleck paramagnetism while GdFe₄P₁₂ is a soft ferromagnet with a Curie temperature of T_C = 22(5) K. Both are metallic conductors. The new isotypic polyarsenide NdFe₄As₁₂ (a = 830.9(1) pm) was obtained by reacting NdAs₂ with iron and arsenic in the presence of a NaCl/KCl flux. The new isotypic polyantimonide Eu_0.54(1)Co₄Sb₁₂ (a = 909.41(8) pm) was prepared by reaction of EuSb₂ with cobalt and antimony. Its structure was refined from single‐crystal X‐ray data to a residual of 0.024 (137 F values, 12 variables). A comparison of the Fe–P and P–P bond lengths in the compounds AFe₄P₁₂, where the A atoms (A = Ce, Eu, Gd, Th) have differing valencies, suggests that the Fermi level cuts through Fe–P bonding and P–P antibonding bands.     

The Nitrido Borates Ln3B2N4 (Ln = La–Nd) and La5B4N9: Syntheses,Structures, and Properties

Single crystals of the lanthanoide nitrido borates Ln₃B₂N₄ (Ln = La–Nd) and La₅B₄N₉ have been obtained from reactions of lanthanoide metal powder, lanthanoide nitride powder, and hexagonal boron nitride in calcium chloride melts. The isotypic compounds Ln₃B₂N₄ belong to the space group Immm (#71), Z = 2, with the lattice parameters for La₃B₂N₄: a = 362.94(3), b = 641.25(6), c = 1097.20(8) pm; Ce₃B₂N₄: a = 356.20(3), b = 631.90(6), c = 1071.91(8) pm; Pr₃B₂N₄: a = 353.46(4), b = 630.04(13), c = 1079.04(23) pm and Nd₃B₂N₄: a = 351.52(4), b = 627.01(15), c = 1075.59(23) pm. The structure of La₅B₄N₉ has been determined in the space group Pbcm (#57), Z = 4, with a = 988.25(5); b = 1263.48(7), c = 770.33(4) pm. These two structure types resemble three kinds of nitrido borate anions, the oxalate analogue B₂N₄ of Ln₃B₂N₄, and the carbonate analogue BN₃ together with the six‐membered ring system B₃N₆ of La₅(BN₃)(B₃N₆). In contrast to the valence compound La₅B₄N₉ the compounds (Ln³⁺)₃(B₂N₄)^8–(e^–) contain one electron in the conduction band, yielding temperature independent paramagnetism for La₃B₂N₄. The calculated electronic structure is developed through the formation of B₂N₄^8– ions by dimerisation of two BN₂ units.     

Ternary Rare Earth Rhodium Antimonides Ln6Rh30Sb19 with Ln = La–Nd,Sm, and Eu

The six title compounds were prepared by annealing cold‐pressed pellets consisting of stoichiometric mixtures of binary rare earth and rhodium antimonides with additional elemental rhodium in evacuated silica tubes. Their crystal structure was determined from four‐circle X‐ray diffractometer data of a Eu₆Rh₃₀Sb₁₉ single crystal, which was isolated from an arc‐melted sample annealed just below the melting temperature in a high‐frequency furnace. It is hexagonal: P6₃/m, a = 1693.2(2) pm, c = 408.11(4) pm, Z = 1. The least‐squares refinement resulted in a residual of R = 0.034 for 1259 structure factors and 62 variable parameters. The structure shows some disorder around the 6₃ axis but otherwise is very similar to the structures of Sc₆Co₃₀Si₁₉ and Yb₆Co₃₀P₁₉, but different from that of U₆Co₃₀Si₁₉. The plot of the cell volumes of the new series Ln₆Rh₃₀Sb₁₉ indicates the europium atoms in Eu₆Rh₃₀Sb₁₉ to be at least partially divalent.     

Sc4Pt7Si2 – An Intergrowth Structure of ScPtSi and ScPt Related Slabs

The metal‐rich silicide Sc₄Pt₇Si₂ was synthesized by arc‐melting. Sc₄Pt₇Si₂ crystallizes with its own structure type, space group Pbam. The structure was refined from single‐crystal X‐ray diffractometer data: a = 647.6(1), b = 1617.1(3), c = 398.96(9) pm, wR2 = 0.0495, 807 F² values and 42 variables. Sc₄Pt₇Si₂ is an intergrowth structure of slightly distorted ScPtSi (TiNiSi type) and ScPt (CsCl type) related slabs. The silicon atoms have the typical coordination number 9 (4 Sc + 5 Pt) in the form of a tricapped trigonal prism. Together, the platinum and silicon atoms build up a complex three‐dimensional [Pt₇Si₂] network with short Pt–Si (238–246 pm) and Pt–Pt (282–303 pm) distances. The scandium atoms fill distorted square prismatic or pentagonal prismatic voids within this network, also with short Sc–Pt distances (276–308 pm). The structural difference of these two scandium species is reflected by substantial discrepancies in ⁴⁵Sc chemical shifts. The quadrupolar interaction parameters that were estimated from the nutation behavior of the two signals were used for an assignment to the two sites.     

Neue Thiophosphate: Die Verbindungen Li6Ln3(PS4)5 (Ln: Y,Gd, Dy,Yb, Lu) und Ag3Y(PS4)2

New Thiophosphates: The Compounds Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) and Ag₃Y(PS₄)₂ The new thiophosphates Li₆Ln₃(PS₄)₅ (Ln: Y, Gd, Dy, Yb, Lu) were synthesized by heating mixtures of Ln, P, S, and Li₂S₄ at 900 °C (100 h) and they were investigated by single crystal X‐ray methods. The compounds with Ln = Y (a = 28.390(2), b = 10.068(1), c = 33.715(2) Å, β = 113.85(1)°), Gd (a = 28.327(2), b = 10.074(1), c = 33.822(2) Å, β = 114.297(7)°), Dy (a = 28.124(6), b = 10.003(2), c = 33.486(7) Å, β = 113.89(3)°), Yb (a = 28.178(3), b = 9.977(1), c = 33.392(4) Å, β = 113.65(1)°), and Lu (a = 28.169(6), b = 10.002(2), c = 33.432(7) Å, β = 113.54(3)°) are isotypic and crystallize in a new structure type (C2/c; Z = 12). Main feature are PS₄ tetrahedra isolated from each other surrounding the Ln and Li atoms via their S atoms. The coordination number of the five crystallographically independent Ln atoms is eight, but the polyhedra are quite different and they are interlinked to larger units extending in [010]. The environment of the Li atoms is irregular and formed by five to six S atoms. The crystal structure is compared with that of Li₉Ln₂(PS₄)₅ (Ln: Nd, Gd). For the synthesis of Ag₃Y(PS₄)₂ (a = 16.874(3), b = 9.190(2), c = 9.312(2) Å, β = 123.17(3)°) a mixture of Y, P, S, and Ag₂S was heated to 700 °C (50 h). The thiophosphate crystallizes in a new structure type (C2/c; Z = 4) composed of isolated PS₄ tetrahedra. The two crystallographically independent Ag atoms are surrounded by four S atoms in the shape of distorted tetrahedra. The Ag(1)S₄ polyhedra are cornershared to strands running along [001], which are linked together via Ag(2)S₄ tetrahedra. The environment of the Y atoms is composed of eight S atoms each building distorted square antiprisms. These polyhedra are connected with each other via common edges to a strand running along [001].     

Ternary Aluminides with the Ideal Composition A2Pt6Al15 (A = Y,Gd—Tm,Zr)

Ternary rare earth platinum aluminides were prepared by arc‐melting of the elemental components followed by annealing in a high‐frequency furnace. Their crystal structure was determined for the yttrium compound from four‐circle X‐ray diffractometer data. It has hexagonal symmetry with a = 428.1(1) pm, c = 1638.3(3) pm, space group P6₃/mmc, and was refined to a conventional residual of R = 0.018 for 325 F values and 19 variable parameters. Of the five crystallographic positions, the yttrium position and one of the three aluminum positions show partial occupancies corresponding to the composition Y_1.357(3)Pt₄Al_9.99(2) with the Pearson symbol hP20 — 4.65. These partially occupied sites are that close to each other that at best only one can be fully occupied. A model for an ordered distribution of occupied and unoccupied Y and Al sites requires a √3 larger a axis with the Pearson symbol hP20 — 4.67 for the subcell, very close to the experimental result. Corresponding superstructure reflections could be observed on an image‐plate single‐crystal diffractometer only in the form of diffuse streaks. The compound has the ideal composition Y₂Pt₆Al₁₅ with Z = 2 for the superstructure. This corresponds to the formula Y_1.33Pt₄Al₁₀ with Z = 1 for the subcell. The compounds A_1.33Pt₄Al₁₀ with A = Gd, Tb, Dy, Ho, Er, Tm were found to be isotypic with that of the yttrium compound. This structure is closely related to or isotypic with, respectively, those of Yb₂Fe₄Si₉, Sc_1.2Fe₄Si_9.8, Ce_1.2Pt₄Ga_9.8, Ce₂Pt₆Ga₁₅, Tb_0.67Ni₂Ga_5—xSi_x, RE_0.67Ni₂Ga_5—xGe_x> (with RE = Y, Sm, Ho), and Gd_0.67Pt₂Al₅, reported in earlier investigations. The new compound Zr_1.00(1)Pt₄Al_10.22(3) has nearly the same hexagonal structure with a = 426.1(1) pm and c = 1622.8(3) pm. It was refined from four‐circle diffractometer data to a residual of R = 0.021 for 288 structure factors and 19 variable parameters.     

Gd3Pt4In12 and Tb3Pt4In12 — New Ternary Indides with Condensed Distorted [PtIn6] Trigonal Prisms

The ternary indium compounds Gd₃Pt₄In₁₂ and Tb₃Pt₄In₁₂ were synthesized from an indium flux. Arc‐melted precursor alloys with the starting compositions ∼GdPtIn₄ and ∼TbPtIn₄ were annealed with a slight excess of indium at 1200 K followed by slow cooling (5 K/h) to 870 K. Both compounds were investigated by X‐ray powder diffraction: a = 990.5(1), c = 1529.5(3) pm for Gd₃Pt₄In₁₂ and a = 988.65(9), c = 1524.0(1) pm for Tb₃Pt₄In₁₂. The structure of the gadolinium compound was solved and refined from single crystal X‐ray data: P3¯m1, wR2 = 0.0470, 1469 F² values and 62 variable parameters. Both crystallographically different platinum sites have a slightly distorted trigonal prismatic indium coordination. These [PtIn₆] prisms are condensed via common edges and corners forming a complex three‐dimensional [Pt₁₂In₃₂] network. The gadolinium, In1 and In7 atoms fill cavities within this polyanion. Tb₃Pt₄In₁₂ is isotypic with the gadolinium compound.     

Synthesis,Structure, Magnetic and Optical Properties of Ternary Thio‐germanates: Ln4(GeS4)3 (Ln = Ce,Nd)

Single crystals of two ternary thio‐germanates containing rare‐earth metals, Ln₄(GeS₄)₃ (Ln = Ce ( I ), Nd ( II )), have been isolated from the reaction of anhydrous rare‐earth trichloride (LnCl₃) and ternary sodium thio‐germanate (Na₂GeS₃) in evacuated quartz ampoules. We have determined the crystal structure of the compounds, which are isostructural to La₄(GeS₄)₃ and crystallize in trigonal system in the space group R3c with the cell dimensions: I , a = b = 19.375(3) Å, c = 8.028(2) Å, Z = 6; II , a = b = 19.250(3) Å, c = 7.949(2) Å, Z = 6. The structure is built with the complex network of two independent tricapped trigonal prisms of CeS₉, in which Ge atoms occupy tetrahedral holes of sulfur atoms. The bulk synthesis of the two compounds has also been achieved by the stoichiometric combination of the elements. The magnetic and optical properties of the compounds have been investigated. The magnetic moments of 2.32 and 3.49 μ_B for I and II , respectively, are in good agreement with the theoretical magnetic moments of Ce and Nd in the +3 oxidation state. The optical band gap of I is found to be located around 2.3 eV, while the optical band gap of II lies around 2.62 eV. In addition, Raman spectroscopic characterizations have also been performed for I , II , and La₄(GeS₄)₃.     

Rare Earth Ruthenium Gallides with the Ideal Composition Ln2Ru3Ga5 (Ln = La–Nd,Sm) crystallizing with U2Mn3Si5 (Sc2Fe3Si5) Type Structure

The rare earth ruthenium gallides Ln₂Ru₃Ga₅ (Ln = La, Ce, Pr, Nd, Sm) were prepared by arc‐melting of cold‐pressed pellets of the elemental components. They crystallize with a tetragonal structure (P4/mnc, Z = 4) first reported for U₂Mn₃Si₅. The crystal structures of the cerium and samarium compounds were refined from single‐crystal X‐ray data, resulting in significant deviations from the ideal compositions: Ce₂Ru_2.31(1)Ga_5.69(1), a = 1135.10(8) pm, c = 580.58(6) pm, R_F = 0.022 for 742 structure factors; Sm₂Ru_2.73(2)Ga_5.27(2), a = 1132.95(9) pm, c = 562.71(6) pm, R_F = 0.026 for 566 structure factors and 32 variable parameters each. The deviations from the ideal compositions 2:3:5 are discussed. A mixed Ru/Ga occupancy occurs only for one atomic site. The displacement parameters are relatively large for atoms with mixed occupancy within their coordination shell and small for atoms with no neighboring sites of mixed occupancy. Chemical bonding is analyzed on the basis of interatomic distances. Ln–Ga bonding is stronger than Ln–Ru bonding. Ru–Ga bonding is strong and Ru–Ru bonding is weak. The Ga–Ga interactions are of similar strength as in elemental gallium.     

Ternary Rare Earth (R) Transition Metal Aluminides R3T4Al12 (T = Ru and Os) with Gd3Ru4Al12 Type Structure

The isotypic intermetallic compounds R₃Ru₄Al₁₂ (R = Y, Pr, Nd, Sm, Gd—Tm) and R₃Os₄Al₁₂ (R = Y, Ce—Nd, Sm, Gd—Tm) were prepared by reaction of the elemental components in an arc‐melting furnace. Their crystal structure was determined from four‐circle X‐ray diffractometer data of Y₃Ru₄Al₁₂: P6₃/mmc, a = 877.7(1) pm, c = 952.3(1) pm, Z = 2, R = 0.028 for 361 structure factors and 28 variable parameters. It was also refined for Nd₃Os₄Al₁₂ (a = 889.2(1) pm, c = 960.3(1) pm, R = 0.021 for 425 F values and 30 variables) and Gd₃Os₄Al₁₂ (a = 884.7(1) pm, c = 955.3(2) pm, R = 0.020; 427 F values, 30 variables). The refinements of the occupancy parameters revealed mixed T/Al occupancy for some of the aluminum sites resulting in the compositions Y₃Ru_4.060(3)Al_11.940(3), Nd₃Os_4.43(1)Al_11.57(1), and Gd₃Os_4.44(1) Al_11.56(1), respectively. The structure is related to those found for Y₂Co₃Ga₉, Er₄Pt₉Al₂₄, CeOsGa₄, Ho₃Ru₄Ga₁₅, YbFe₂Al₁₀, TbRe₂Al₁₀, LuRe₂Al₁₀, and CaCr₂Al₁₀. Topologically all of these structures may be viewed as consisting of atomic layers, although chemical bonding within and between the layers is of similar character. Two kinds of layers can be distinguished in these structures. One kind contains all of the rare earth (occasionally also alkaline earth) and in addition aluminum or gallium atoms. The other kind of layers consists of the transition metal atoms and again aluminum or gallium atoms. These latter layers are hexa gonally close packed and slightly puckered. The three different structures of the disilicides TiSi₂, CrSi₂, and MoSi₂ also contain these layers; however, in the disilicides these layers are flat.