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.     

Die Kristallstruktur von Zr2Al und Hf2Al

Zusammenfassung Im Zweistoff: Zr–Al bzw. Hf–Al werden zwei neue Kristallarten Zr₂Al und Hf₂Al mit CuAl₂-Struktur nachgewiesen; die Parameter sind:a=6,840 bzw. 6,76₂ undc=5,49₀ bzw. 5,37₄ kX·E. In den Dreistoffen: Zr–Al–Si und Hf–Al–Si besteht jeweils ein lückenloser Übergang zwischen den isotypen Phasen Zr₂Al und Zr₂Si bzw. Hf₂Al und Hf₂Si.     

Die Kristallstruktur von Zr(Sn,Sb)2

Ohne Zusammenfassung     

Die Kristallstruktur von SrCaCrF7

The Crystal Structure of SrCaCrF₇ By solid state reaction of the component fluorides at elevated temperature single crystals of SrCaCrF₇ were obtained (a = 792.3(2), b = 724.7(2), c = 986.1(2) pm; space group Pnma, Z = 4). The X‐ray structure determination confirmed isotypism with the Ca₂AlF₇ type of structure: Isolated octahedra [CrF₆]^3— (mean Cr‐F: 189.7 pm) are opposed by infinitely netted planar cations [SrFCa_2/2]³⁺ which contain “independent” F atoms 3‐coordinated by alkaline earth atoms only. The Sr atoms prefer (at a level of 80%) the 8‐fold, the Ca atoms the 7‐fold coordinated positions between the octahedra.     

Die Kristallstruktur von KPdMIVF7 (MIV = Zr,Hf)

The Crystal Structure of KPdM^IVF₇ (M^IV = Zr, Hf) Blue single crystals of KPdZrF₇ are obtained by heating the binary fluorides in sealed Pt-tubes under dry argon (solid state reaction, T ≈? 720°C, t ≈? 14 d). The compound crystallizes orthorhombically in the space group Pnna-D (Nr. 52); lattice parameters are a = 1 132.3(5) pm, b = 797.5(2) pm, c = 639.8(1) pm; Z = 4 (Four cycle diffractometer data, AED2). According to [F₄PdF_2/1ZrF₅] distortet [PdF₆]-octaedra are connected with pentagonal-bipyramidal [ZrF₇]-polyhedra via two bridging F^?, resulting in [PdZrF₁₁]-groups. These [PdZrF₁₁]-groups built up a threedimensional-network with K⁺ in its spacings. KPdHfF₇ crystallizes isotypically (a = 1 136.1(3) pm, b = 796.4(2) pm und c = 638.8(1) pm; four cycle diffractometer data, AED2).     

Die Kristallstruktur von Ca2As2O7

The structure of Ca₂As₂O₇ (a ₀=7.05,b ₀=9.30,c ₀=4.89 Å; =101.3°; space groupC2/m-C _2h ³ ;Z=2) has been solved from 465 independent X-ray intensities collected on aWeissenberg-type diffractometer up to anR-factor of 2.4% for all intensities. The structure of Ca₂As₂O₇ represents a further Thortveitite structure type.

     

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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Die Kristallstruktur von RhHg2

Zusammenfassung RhHg₂ kristallisiert tetragonal mita=4,55₁ Å,c=2,99₈ Å,c/a=0.658₈ in der Raumgruppe P 4/mmm. Die Phase ist isotyp mit -PtHg₂.

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The structure of RhHg₂ was found to be tetragonal; the unit cell ofa=4,55₁ Å,c=2,99₈ Å,c/a=0,658₈ belongs to the space group P 4/mmm. RhHg₂ is isostructural with -PtHg₂.

     

Die Kristallstruktur von TaNi2

Zusammenfassung TaNi₂ kristallisiert im MoSi₂-Typ.     

Die Kristallstruktur von CuBr · (C2H5)4P2

The crystal structure of CuBr · (C₂H₅)₄P₂ has been determined by single crystal X-ray methods. The crystals are triclinic (space group P 1 ) with two formula units per unit cell (a) = 9,29, b = 9,92, c = 7,57 Å, α = 85,3°, β = 106,6°, γ = 109,1°. The copper atoms are tetrahedrally coordinated by two bromine and two phosphorus atoms (of different biphosphine molecules). The structure has continuous chains running parallel c, in which the copper atoms are linked together by alternating double bridges consisting of two biphosphine molecules and two bromine atoms, respectively.     

Die Kristallstruktur von PrTe2

The Crystal Structure of PrTe₂ X‐ray diffraction single‐crystal structure analysis of PrTe₂ prepared by chemical vapour transport reactions starting with praseodymium and tellurium in the presence of trace amounts of iodine also revealed superstructure reflections indicating just as for CeTe₂ a (2 × 2 × 2)‐supercell of the basic anti‐Fe₂As‐type structure instead of a (2 × 2 × 1)‐supercell as for LaTe₂. In contrast to LaTe₂ with monoclinic symmetry (space group P1c1), PrTe₂ crystallizes tetragonal in the space group P4 with the lattice parameters a = 896.80(5) pm and c = 1811.9(1) pm (Z = 16). The doubling of the c‐lattice parameter compared to LaTe₂ is observed due to different polyanionic structural motifs in the heights z ≈ 0 and z ≈ ¹/₂. These are a herringbone pattern of [Te₂] dumbbell pairs (motif A; a topology which is also found in LaTe₂), isolated square four‐membered [Te₄] rings in z ≈ 0 (motif B) and additionally rectangular four‐membered [Te₄] rings in z ≈ ¹/₂ (motif C). Though CeTe₂ and PrTe₂ are crystallizing isotypically, there are distinct differences in the interatomic distances within the polyanionic Te layers and resulting from these also a different topology of the structural motif C. The individual structural elements are causing a diffraction pattern, which is all in all to be explained by a statistical superposition of the different elements in form of microdomains.     

Die Kristallstruktur von NaBiO2

The crystal structure of NaBiO₂ NaBiO₂ crystallizes monoclinic in C with a = 7.39₄, b = 7.26₂, c = 5.88₆ Å, β = 127.7°; Z = 4. Parameters were refined by least-squares (555 hkl with |h?l| = 0 to 4; R = 10.9%). Angular groups [BiO₂] are twisted by 180°, forming chains [BiO_2/2O_2/2] along [001]. The MADELUNG part of lattice energy (MAPLE) is calculated and discussed.     

Die Kristallstruktur von LiInSe2

The Crystal Structure of LiInSe₂ The crystal structure of LiInSe₂ has been determined from single crystal data (β-NaFeO₂ type, space group Pna2₁ (No. 33), a = 718.3(2), b = 839,8(3), c = 678.1(2) pm; 375 hkl, R = 0.032; R(w) = 0.029). The mean values 253.6 pm of the bond distances Li? Se are larger than calculated, the distances In? Se (256.8 pm) are equal with the calculated values. The structure is discussed in relation to the analogous LiB^IIIC₂^VI compounds.     

Die Kristallstruktur von Hf2Hg

Zusammenfassung Im System Hafnium-Quecksilber wurde im Temperaturbereich zwischen 500° C und 800° C nur eine Verbindung Hf₂Hg gefunden. Für diese Verbindung wird eine tetragonale Elementarzelle mita=3,34₅ Å,c=11,49₆ Å,c/a=3,436, Raumgruppe D _4h ¹⁷ –I 4/mmm vom MoSi₂-Typ vorgeschlagen.

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Investigations in the system hafnium—mercury have shown the existence of only one intermetallic compound Hf₂Hg. The structure is supposed to be tetragonal of the MoSi₂-type,a=3.34₅ Å,c=11.49₆ Å,c/a=3.436, belonging to the space group D _4h ¹⁷ –I 4/mmm.

     

Synthese und Kristallstruktur von Pb2P4O12 · 3 H2O

Synthesis and Crystal Structure Determination of Pb₂P₄O₁₂ · 3 H₂O Pb₂P₄O₁₂ · 3 H₂O precipitates at mixing aqueous solutions of Pb(NO₃)₂ and Na₄P₄O₁₂ (25°C). Crystal growth was achieved by applying gel-techniques (Agar-Agar-gel). The crystal structure (P1 , a = 786.4(3), b = 914.4(3), c = 1021.6(3) pm, α = 97.42(2)°, β = 100.63(2)°, γ = 114.92(2)°; Z = 2; 4160 unique diffractometer data, R = 0.05) contains cyclo-tetraphosphate anions with point symmetry D_2d. Lead is coordinated by eight oxygen, the polyhedra deriving from a square antiprism.     

Synthese und Kristallstruktur von Sr2Rh7P6

Synthesis and Crystal Structure of Sr₂Rh₇P₆ Single crystals of Sr₂Rh₇P₆ were obtained by reaction of the elements in molten lead at 1100 °C and investigated by X-ray methods. The compound crystallizes tetragonally (a = 11.080(2), c = 4.098(1) Å) and forms a crystal structure (P 4 2₁m; Z = 2) with ThCr₂Si₂ analogous units, which are linked with each other in a new way. Therefore the RhP₄ tetrahedra form bands of edge sharing chains parallel to [001] anstead of layers as in the ThCr₂Si₂ type structure. The arrangement enables a part of the P atoms to form short P–P distances of 2,26 Å and space for additional Rh atoms with a likewise distorted tetrahedral coordination of P atoms is obtained.     

Die Kristallstruktur von V2C

Zusammenfassung V₂C kristallisiert je nach Art der Entstehung in einer orthorhombischen Form (-Fe₂N-Typ) oder mit der bekannten hexagonalen Struktur.

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The subcarbide V₂C crystallizes with an orthorhombic cell (-Fe₂N) as well as with the known hexagonal cell depending on the mode of formation.

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Die Kristallstruktur von Mo2FeB2

Zusammenfassung Mo₂FeB₂ wird aus den Elementen synthetisiert. Diese Phase ist mit U₃Si₂ isotyp, jedoch mit Ordnung der Mo- und Fe-Atome.