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.     

Die Kristallstruktur von Co4Hf2P3

Zusammenfassung Die Struktur einer ternären Phase mit der Idealzusammensetzung Co₄Hf₂P₃ wurde röntgenographisch mittels Einkristallmethoden bestimmt und verfeinert. Die Gitterparameter der hexagonalen Elementarzelle sinda=12,0559 undc=3,6249 Å, die Raumgruppe ist . Die Phase ist strukturell mit Fe₂P und Fe₁₂Zr₂P₇ verwandt.

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The structure of a ternary phase with the ideal composition Co₄Hf₂P₃ has been determined and refined by means of singlecrystal X-ray methods. The cell dimensions of the hexagonal unit cell are found to be:a=12,0559 andc=3,6249 Å, the space group is . The phase is structurally related to Fe₂P and Fe₁₂Zr₂P₇.

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Neue Verbindungen mit Zr2Fe12P7-Struktur und Verfeinergung der Kristallstrukturen von Er2Co12P7 und Er2Ni12P7

New Compounds Zr₂Fe₁₂P₇-Type Structure and Refinement of the Crystal Structures of Er₂Co₁₂P₇ and Er₂Ni₁₂P₇ The compounds Y₂Ni₁₂P₇ and Ln₂Ni₁₂P₇ (Ln = Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Lu) were prepared for the first time and characterized by their lattice constants. Their crystal structure corresponds to that of Zr₂Fe₁₂P₇. The structure of Er₂Co₁₂O₇ and Er₂Ni₁₂P₇ were refined from single-crystal counter data. Chemical bonding and the question of the proper space group for those and the closely related compounds V₁₂P₇ and Cr₁₂P₇ are discussed.     

Synthese und Struktur von RbHfF5, Rb2Zr3F12O und Rb2Hf3F12O — zwei Oxidfluoride mit zentraler trigonal‐planarer [M3O]‐Gruppe

Synthesis and Structure of RbHfF₅, Rb₂Zr₃F₁₂O and Rb₂Hf₃F₁₂O — two Oxydefluorides with Central Trigonal‐plane [M₃O] Group Colorless RbHfF₅ crystallizes isotypic with (NH₄)ZrF₅ and TlHfF₅ monoclinic, space group P2₁/c ‐ C_2h (No. 14) with a = 776.6, b = 789.6, c = 789.8 pm, and β = 120.52°. Also colorless Rb₂Zr₃F₁₂O crystallizes trigonal, space group R3¯m — D₃d (No. 166), with a = 771.9 and c = 2963.0 pm, isotypic is Rb₂Hf₃F₁₂O with a = 769.2 pm and c = 2986.1 pm. Both compounds are isotypic with Tl₂Zr₃F₁₂O.     

The Reconstructive Phase Transformation β‐Co2P → α‐Co2P and the Structure of the High‐Temperature Phosphide β‐Co2P

Metallographical and differential thermoanalytical (DTA) investigatitons indicate that the well known phosphide Co₂P (Pearson code oP12, space group Pnma, Co₂Si type) is not stable up to the melting point, T = 1659 K; it is therefore designated as the low‐temperature phase α‐Co₂P. In the temperature range from 1428 to 1659 K, another, high‐temperature phase, designated as β‐Co₂P, exists. X‐ray powder diffraction investigation of liquid quenched alloys in the composition range x_P = 0.25 to 0.335, with x_P as the mole fraction, show that the high‐temperature phase β‐Co₂P is isotypic with Fe₂P (hP9, P 6 2m). For the ideal composition Co₂P, the unit cell parameters are: a = 5.742(2) Å, c = 3.457(5) Å, c/a = 0.621. Among the binary transition metal‐containing phosphides and arsenides isotypic with Fe₂P, β‐Co₂P is the only known high‐temperature phase and it shows (i) the highest axial ratio c/a and (ii) the “smallest” distortion of the hcp substructure formed by the transition metals atoms in the Fe₂P structure type.     

Die Kristallstruktur von Fe12Zr2P7

Zusammenfassung Die Struktur einer ternären Phase im System Fe–Zr–P wurde mit Hilfe von Einkristallaufnahmen bestimmt und verfeinert. Die Kristallart entspricht der vonVogel undDobbener aufgefundenen Phase Fe₄ZrP₂ und hat eine Idealzusammensetzung von Fe₁₂Zr₂P₇. Die Gitterparameter der hexagonalen Kristallart sinda=9,0002 undc=3,5920 Å, die Raumgruppe ist . Die Struktur ist mit jener von Fe₂P verwandt.

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The crystal structure of a ternary phase in the system Fe–Zr–P has been determined and refined by means of singlecrystal X-ray methods. The phase, already described byVogel andDobbener as Fe₄ZrP₂, has the ideal composition Fe₁₂Zr₂P₇. The cell dimensions are found to be:a=9,0002 andc=3,5920 Å, the space group is . The crystal structure of Fe₁₂Zr₂P₇ is related to Fe₂P.

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Metal-rich phosphides RE5Ir19P12 with Sc5Co19P12 type structure

The iridium-rich phosphides RE₅Ir₁₉P₁₂ (RE=Sc, Y, La–Nd, Sm–Lu) with Sc₅Co₁₉P₁₂ type structure, space group P62?m were synthesized by solid state reactions of the elements in tantalum crucibles. Well shaped single crystals were obtained in bismuth fluxes. All phosphides were characterized on the basis of X-ray powder data. The structures of RE₅Ir₁₉P₁₂ with RE=Sc, La, Ce, Dy, Er, Tm, and Yb were refined from single crystal diffractometer data. The complex structure of these phosphides can be described by an intergrowth of simpler ThCr₂Si₂ and SrPtSb related slabs. Striking structural motifs of the RE₅Ir₁₉P₁₂ structures are slightly distorted tricapped trigonal prisms of the metal atoms around the phosphorus atoms. The iridium and phosphorus atoms build up three-dimensional [Ir₁₉P₁₂] polyanionic networks (230–286 pm Ir–P and 282–296 pm Ir–Ir in La₅Ir₁₉P₁₂) which leave cavities of coordination numbers 16 and 15 for the rare earth atoms.     

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.     

Synthese und Struktur der Phosphor-verbrückten Übergangsmetallkomplexe [Fe2(CO)6(PR)6] (R = tBu,iPr), [Fe2(CO)4(PiPr)6], [Fe2(CO)3Cl2(PtBu)5], [Co4(CO)10(PiPr)3], [Ni5(CO)10(PiPr)6] und [Ir4(C8H12)4Cl2(PPh)4]

Synthesis and Structure of the Phosphorus-bridged Transition Metal Complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu, ⁱPr), [Fe₂(CO)₄(PⁱPr)₆], [Fe₂(CO)₃Cl₂(P^tBu)₅], [Co₄(CO)₁₀(PⁱPr)₃], [Ni₅(CO)₁₀(PⁱPr)₆], and [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] (P^tBu)₃ and (PⁱPr)₃ react with [Fe₂(CO)₉] to form the dinuclear complexes [Fe₂(CO)₆(PR)₆] (R = ^tBu: 1 ; ⁱPr: 2 ). 2 is also formed besides [Fe₂(CO)₄(PⁱPr)₆] ( 3 ) in the reaction of [Fe(CO)₅] with (PⁱPr)₃. When PⁱPr(P^tBu)₂ and PⁱPrCl₂ are allowed to react with [Fe₂(CO)₉] it is possible to isolate [Fe₂(CO)₃Cl₂(P^tBu)₅] ( 4 ). The reactions of (PⁱPr)₃ with [Co₂(CO)₈] and [Ni(CO)₄] lead to the tetra- and pentanuclear clusters [Co₄(CO)₁₀(PⁱPr)₃] ( 5 ), [Ni₄(CO)₁₀(PⁱPr)₆] [2] and [Ni₅(CO)₁₀(PⁱPr)₆] ( 6 ). Finally the reaction of [Ir(C₈H₁₂)Cl]₂ with K₂(PPh)₄ leads to the complex [Ir₄(C₈H₁₂)₄Cl₂(PPh)₄] ( 7 ). The structures of 1–7 were obtained by X-ray single crystal structure analysis (1: space group P2₁/c (Nr. 14), Z = 8, a = 1 758.8(16) pm, b = 3 625.6(18) pm, c = 1 202.7(7) pm, β = 90.07(3)°; 2 : space group P1 (Nr. 2), Z = 1, a = 880.0(2) pm, b = 932.3(3) pm, c = 1 073.7(2) pm, α = 79.07(2)°, β = 86.93(2)°, γ = 72.23(2)°; 3 : space group Pbca (Nr. 61), Z = 8, a = 952.6(8) pm, b = 1 787.6(12) pm, c = 3 697.2(30) pm; 4 : space group P2₁/n (Nr. 14), Z = 4, a = 968.0(4) pm, b = 3 362.5(15) pm, c = 1 051.6(3) pm, β = 109.71(2)°; 5 : space group P2₁/n (Nr. 14), Z = 4, a = 1 040.7(5) pm, b = 1 686.0(5) pm, c = 1 567.7(9) pm, β = 93.88(4)°; 6 : space group Pbca (Nr. 61), Z = 8, a = 1 904.1(8) pm, b = 1 959.9(8) pm, c = 2 309.7(9) pm. 7 : space group P1 (Nr. 2), Z = 2, a = 1 374.4(7) pm, b = 1 476.0(8) pm, c = 1 653.2(9) pm, α = 83.87(4)°, β = 88.76(4)°, γ = 88.28(4)°).     

Das System Gd/Co/B: Darstellung und röntgenographische Charakterisierung von GdCo4B,Gd3Co11B4, GdCoB4 und GdCo12B6

The System Gd/Co/B: Preparation and Characterization by X‐ray Diffraction of GdCo₄B, Gd₃Co₁₁B₄, GdCoB₄, and GdCo₁₂B₆ The compounds GdCo₄B, Gd₃Co₁₁B₄, GdCoB₄, and GdCo₁₂B₆ were characterized by X‐ray investigations of single crystals. GdCo₄B (P 6/mmm, a = 505.9(1) pm, c = 690.1(1) pm) crystallizes with the CeCo₄B structure type; Gd₃Co₁₁B₄ (P 6/mmm, a = 508.7(1) pm, c = 982.9(9) pm) with the Ce₃Co₁₁B₄ stucture type; GdCo₁₂B₆ ( , a = 949.5(1) pm, c = 747.4(1) pm) with the SrNi₁₂B₆ structure type and GdCoB₄ (P bam, a = 591.3(9) pm, b = 1145.1(6) pm, c = 346.2(3) pm) with the YbCoB₄ structure type.     

Preparation and Crystal Structure of the Ternary Lanthanoid Platinum Antimonides Ln3Pt7Sb4 (Ln = Ce,Pr, Nd,and Sm) with Er3Pd7P4 Type Structure

The four compounds Ln₃Pt₇Sb₄ (Ln = Ce, Pr, Nd, and Sm) were prepared from the elements by arc‐melting and subsequent heat treatment in resistance and high‐frequency furnaces. The crystal structure of these isotypic compounds was determined from four‐circle X‐ray diffractometer data of Nd₃Pt₇Sb₄ [C2/m, a = 1644.0(2) pm, b = 429.3(1) pm, c = 1030.6(1) pm, β = 128.58(1)°, Z = 2, R = 0.032 for 698 structure factors and 46 variable parameters] and Sm₃Pt₇Sb₄ [a = 1639.5(2) pm, b = 427.1(1) pm, c = 1031.8(1) pm, β = 128.76(1)°, Z = 2, R = 0.025 for 816 F‐values and 46 variables]. The structure is isotypic with that of the homologous phosphide Er₃Pd₇P₄. In contrast to the structure of this phosphide, where the phosphorus atoms have the coordination number nine, the larger antimony atoms of Nd₃Pt₇Sb₄ obtain the coordination number ten. The structural relationships between the structures of EuNi_2—xSb₂, EuPd₂Sb₂, CeNi_2+xSb_2—x, Ce₃Pd₆Sb₅, and Nd₃Pt₇Sb₄, all closely related to the tetragonal BaAl₄ (ThCr₂Si₂) type structure, are briefly discussed emphasizing their space group relationships.     

Zr7(Sb,Se)4 – eine polare Variante des Nb7P4-Strukturtyps

Zr₇(Sb,Se)₄ – a Polar Variant of the Nb₇P₄ Structure Type Single crystals of Zr₇Sb_1.6(1)Se_2,4 were obtained by arc-melting of compressed mixtures of Zr, ZrSb₂, and ZrSe₂, followed by annealing at 1300 °C in an induction furnace using traces of iodine to promote crystal growth. The crystal structure (a = 375.98(4), b = 1662.6(2), c = 1476.7(2) pm, V = 923.1(2) 10⁶ pm³, Cmc2₁, Z = 4) was determined by single crystal X-ray means. Zr₇Sb_1.6(1)Se_2.4 forms a unique polar structure composed of condensed tri-capped trigonal prismatic Zr₉ clusters, being stabilized by interstitial Sb/Se atoms. The remaining Sb and Se atoms reside in mono- and bi-capped trigonal prismatic Zr₇ and Zr₈ clusters, respectively, of the extended cluster network. Characteristic structural distinctions and relations between Zr₇(Sb,Se)₄ and congeneric Zr₇P₄ are highlighted.     

[Co4P2(PtBu2)2(CO)8] und [{Co(CO)3}2P4tBu4] aus Co2(CO)8 und tBu2P–P=P(Me)tBu2

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XIX. [Co₄P₂(P^tBu₂)₂(CO)₈] and [{Co(CO)₃}₂P₄^tBu₄] from Co₂(CO)₈ and ^tBu₂P–P=P(Me)^tBu₂ Co₂(CO)₈ reacts with ^tBu₂P–P=P(Me)^tBu₂ yielding the compounds [Co₄P₂(P^tBu₂)₂(CO)₈] ( 1 ) and [{η^2tBu₂P=P–P=P^tBu₂}{Co(CO)₃}₂] ( 2 a ) cis, ( 2 b ) trans. In 1 , four Co and two P atoms form a tetragonal bipyramid, in which two adjacent Co atoms are μ₂‐bridged by ^tBu₂P groups. Additionally, two CO groups are linked to each Co atom. In 2 a and 2 b , each of the Co(CO)₃ units is η²‐coordinated to the terminal P₂ units resulting in the cis‐ and trans‐configurations 2 a and 2 b . 1 crystallizes in the orthorhombic space group Pnnm (No. 58) with a = 879,41(5), b = 1199,11(8), c = 1773,65(11) pm. 2 a crystallizes in the monoclinic space group P2₁/n (No. 14) with a = 875,97(5), b = 1625,36(11), c = 2117,86(12) pm, β = 91,714(7)°. 2 b crystallizes in the triclinic space group P 1 (No. 2) with a = 812,00(10), b = 843,40(10), c = 1179,3(2) pm, α = 100,92(2)°, β = 102,31(2)°, γ = 102,25(2)°.     

Neue Phosphor-verbrückte Übergangsmetall-Komplexe Die Kristallstrukturen von [Co4(CO)10(PiPr)2], [Fe3(CO)9(PtBu)(PPh)], [Cp3Fe3(CO)2(PPtBu)(PtBu)], [(NiPPh3)2(PiPr)6], [(NiPPh3)Ni{(PtBu)3}2] und [Ni8(PtBu)6(PPh3)2]

New Phosphorus-bridged Transition Metal Complexes The Crystal Structures of [Co₄(CO)₁₀(PⁱPr)₂], [Fe₃(CO)₉(P^tBu)(PPh)], [Cp₃Fe₃(CO)₂(PP^tBu)· (P^tBu)], [(NiPPh₃)₂(PⁱPr)₆], [(NiPPh₃)Ni{(P^tBu)₃}₂], and [Ni₈(P^tBu)₆(PPh₃)₂] By the reaction of cyclophosphines with transition metal carbonyl-derivatives polynuclear complexes are built, in which the PR-ligands (R = organic group) are bonded in different ways to the metal. Depending on the reaction conditions the following compounds can be characterized: [Co₄(CO)₁₀ · (PⁱPr)₂] ( 2 ), [Fe₃(CO)₉(P^tBu)(PPh)] ( 3 ), [Cp₃Fe₃(CO)₂(PP^tBu) · (P^tBu)] ( 4 ), [(NiPPh₃)₂(PⁱPr)₆] ( 5 ), [(NiPPh₃)Ni{(P^tBu)₃}₂] ( 6 ) and [Ni₈(P^tBu)₆(PPh₃)₂] ( 7 ). The structures of 2–7 were obtained by X-ray single crystal structure analysis ( 2 : space group Pccn (No. 56), Z = 4, a = 1001,4(2) pm, b = 1375,1(3) pm, c = 1675,5(3) pm; 3 : space group P2₁ (No. 4), Z = 2, a = 914,3(4) pm, b = 1268,7(4) pm, c = 1028,2(5) pm, β = 101,73(2)°; 4 : space group P1 (No. 2), Z = 2, a = 946,0(5) pm, b = 1074,4(8) pm, c = 1477,7(1,0) pm, α = 107,63(5)°, β = 94,66(5)°, γ = 111,04(5)°; 5 : space group P1 (No. 2), Z = 2, a = 1213,6(2) pm, b = 1275,0(2) pm, c = 2038,8(4) pm, α = 92,810(10)°, β = 102,75(2)°, γ = 93,380(10)°; 6 : space group P1 (No. 2), Z = 2, a = 1157,5(5) pm, b = 1371,9(6) pm, c = 1827,6(10) pm; α = 69,68(3)°, β = 80,79(3)°, γ = 69,36(3)°; 7 : space group P3 (No. 147), Z = 1, a = 1114,1(2) pm, b = 1114,1(2) pm, c = 1709,4(3) pm).     

Yb2+3—xPd12—3+xP7 (x = 0.40): Different Ytterbium Species in a Substituted Structural Motif of the Zr2Fe12P7 Type

The new compound Yb_2+3—xPd_12—3+xP₇ x = 0.40(4)) was synthesized by sintering of a mixture of elemental components at 1100 °C with subsequent annealing at 800 °C. The crystal structure of Yb_2+3—xPd_12—3+xP₇ was solved and refined from X‐ray single‐crystal diffraction data: space group P6¯, a = 10.0094(4)Å, c = 3.9543(2)Å, Z = 1; R(F) = 0.022 for 814 observed unique reflections and 38 refined parameters. The atomic arrangement reproduces a structure motif of the hexagonal Zr₂Fe₁₂P₇ type in which one of the transition metal positions is substituted predominantly by ytterbium (Yb : Pd = 0.86(1) : 0.14). The ytterbium atoms are embedded in the 3D polyanion formed by palladium and phosphorus atoms. Two different environments for ytterbium atoms are present in the structure. Magnetic susceptibility measurements and XAS spectroscopy at the Yb L_III edge show the presence of ytterbium in two electronic configurations, 4?¹³ and 4?¹⁴. The following model was derived. Ytterbium atoms in the 3k site are in the 4?¹³ state, the two remaining positions contain ytterbium in intermediate‐valence states, giving totally 79 % ytterbium in the 4?¹³ electronic configuration.     

Phosphides with Zr2Fe12P7-type structure

Twenty-six ternary phosphides Ln₂T₁₂P₇ (Ln = lanthanoid, T = Fe, Co, Ni) were prepared for the first time by reaction of the elemental components in liquid tin or by reaction of the components in evacuated silica tubes. The analysis of their powder patterns indicates their isotypism with Zr₂Fe₁₂P₇. Their lattice constants are reported. Gd₂Ni₁₂As₇ also crystallizes with that structure.     

Isotype Borophosphate MII(C2H10N2)[B2P3O12(OH)] (MII = Mg,Mn, Fe,Ni, Cu,Zn): Verbindungen mit Tetraeder‐Schichtverbänden

Isotypic Borophosphates M^II(C₂H₁₀N₂)[B₂P₃O₁₂(OH)] (M^II = Mg, Mn, Fe, Ni, Cu, Zn): Compounds containing Tetrahedral Layers The isotypic compounds M^II(C₂H₁₀N₂) · [B₂P₃O₁₂(OH)] (M^II = Mg, Mn, Fe, Ni, Cu, Zn) were prepared under hydrothermal conditions (T = 170 °C) from mixtures of the metal chloride (chloride hydrate, resp.), Ethylenediamine, H₃BO₃ and H₃PO₄. The orthorhombic crystal structures (Pbca, No. 61, Z = 8) were determined by X‐ray single crystal methods (Mg(C₂H₁₀N₂)[B₂P₃O₁₂(OH)]: a = 936.81(2) pm, b = 1221.86(3) pm, c = 2089.28(5) pm) and Rietveld‐methods (M^II = Mn: a = 931.91(4) pm, b = 1234.26(4) pm, c = 2129.75(7) pm, Fe: a = 935.1(3) pm, b = 1224.8(3) pm, c = 2088.0(6) pm, Ni: a = 939.99(3) pm, b = 1221.29(3) pm, c = 2074.05(7) pm, Cu: a = 941.38(3) pm, b = 1198.02(3) pm, c = 2110.01(6) pm, Zn: a = 935.06(2) pm, b = 1221.33(2) pm, c = 2094.39(4) pm), respectively. The anionic part of the structure contains tetrahedral layers, consisting of three‐ and nine‐membered rings. The M^II‐ions are in a distorted octahedral or tetragonal‐bipyramidal [4 + 2] (copper) coordination formed by oxygen functions of the tetrahedral layers. The resulting three‐dimensional structure contains channels running along [010]. Protonated Ethylenediamine ions are fixed within the channels by hydrogen bonds.     

Syntheses and Crystal Structures of the Cyclotriphosphate Hydrates Nd(P3O9)·3H2O,Nd(P3O9)·4.5H2O,RE(P3O9)·5H2O (RE = Pr,Nd), and Na3RE(P3O9)2·6H2O (RE = Pr,Nd)

Several rare‐earth cyclotriphosphate hydrates were obtained from mixtures of sodium cyclotriphosphates and the respective rare‐earth chlorides. Nd(P₃O₉) · 3H₂O [P$\bar{6}$ , Z = 3, a = 677.90(9), c = 608.67(9) pm, R₁ = 0.016, wR₂ = 0.038, 312 data, 36 parameters] was obtained by a solid state reaction and is isotypic with respective rare‐earth phosphate hydrates, while all the others adopt new structure types. Nd(P₃O₉) · 4.5H₂O [C2/c, Z = 8, a = 1644.6(3), b = 756.11(15), c = 1856.1(4) pm, β = 97.25(3)°, R₁ = 0.032, wR₂ = 0.081, 1763 data, 194 parameters], Nd(P₃O₉) · 5H₂O [P2₁/c, Z = 4, a = 773.75(15), b = 1149.1(2), c = 1394.9(3) pm, β = 106.07(3)°, R₁ = 0.042, wR₂ = 0.082, 1338 data, 194 parameters], Pr(P₃O₉) · 5H₂O [P$\bar{1}$ , Z = 2, a = 745.64(15), b = 889.07(18), c = 934.55(19) pm, α = 79.00(3), β = 80.25(3), γ = 66.48(3), R₁ = 0.059, wR2 = 0.089, 1468 data, 193 parameters], Na₃Nd(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1059.78(18), b = 1207.25(15), c = 1645.7(4) pm, β = 99.742(17), R₁ = 0.047, wR₂ = 0.119, 1109 data, 351 parameters] and Na₃Pr(P₃O₉)₂ · 6H₂O [P2₁/n, Z = 4, a = 1061.42(16), b = 1209.0(2), c = 1635.5(3) pm, β = 99.841(13), R₁ = 0.035, wR₂ = 0.062, 1323 data, 350 parameters] were obtained by careful crystallization at room temperature. A thorough structure discussion is given. The infrared spectrum of Nd(P₃O₉) · 4.5H₂O is also reported.     

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.     

Preparation and Crystal Structures of some Binary Pnictides of Scandium,Zirconium, and Hafnium: Sc5Bi3, ZrBi, α‐HfSb,HfBi, HfBi2, and the Compound Zr5Bi3X1–x,Possibly Stabilized by an Impurity (X)

The title compounds were prepared by reaction of the elemental components. Of these Sc₅Bi₃ is a new compound. Its orthorhombic β‐Yb₅Sb₃ type crystal structure was determined from single‐crystal X‐ray data: Pnma, a = 1124.4(1) pm, b = 888.6(1) pm, c = 777.2(1) pm, R = 0.024 for 1140 structure factors and 44 variable parameters. For the other compounds we have established the crystal structures. ZrBi has ZrSb type structure with a noticeable homogeneity range. This structure type was also found for the low temperature (α) form of HfSb and for HfBi. For α‐HfSb this structure was refined from single‐crystal X‐ray data: Cmcm, a = 377.07(4) pm, b = 1034.7(1) pm, c = 1388.7(1) pm, R = 0.043 for 432 F values and 22 variables. HfBi₂ has TiAs₂ type structure: Pnnm, a = 1014.2(2) pm, b = 1563.9(3) pm, c = 396.7(1) pm. The structure was refined from single‐crystal data to a residual of R = 0.074 for 1038 F values and 40 variables. In addition, a zirconium bismuthide, possibly stabilized by light impurity elements X and crystallizing with the hexagonal Mo₅Si₃C_1–x type structure, was observed: Zr₅Bi₃X_1–x, a = 873.51(6) pm, c = 599.08(5) pm. The positions of the heavy atoms of this structure were refined from X‐ray powder film data. Various aspects of impurity stabilization of intermetallics are discussed.