Hanskarl Müller-Buschbaum

Zwei neue Oxopalladate: BaPdNd2O5 und BaPdSm2O5 mit planar koordinierten Pd2+-Ionen

Single crystals of BaPdNd2O5 (A), BaPdSm2O5 (B) and BaCuNd2O5 (C) were prepared by solid state reaction using BaCl2 as a fusing assistant (A, B) or by high temperature Laser technique (C). X-ray investigations show tetragonal symmetry with A:a=6.7387 (5),c=5.9002 (25) Å, B:a=6.6667 (13),c=5.8800 (6) Å (space group D4h5−P4/mbm,Z=2). The formerly investigated compound (C) is refined here by single crystal data. (A) and (B) belong to the BaPtNd2O5-type. The results are discussed.

Neue Verbindungen zum BaNiNd2O5-Typ: BaNiLn2O5 (Ln=Sm, Gd, Ho, Er, Tm)

Five new compounds of the BaNiNd2O5-type with the rare earth elements Sm, Gd, Ho, Er, Tm are prepared and examined by X-ray single crystal technique. The atomic parameters are refined by least-square methods. The crystal chemical differences in the surrounding of rare earth ions in BaMLn2O5-compounds (M=Pt, Pd, Cu, Ni) are discussed.

Über ein neues Oxoiridat(IV): Ba7Ir6O19

SummaryThe so far unknown compound Ba7Ir6O19 was prepared by long time solid state reactions using a flux of BaCl2. X-ray single crystal work lead to the space group C2h3—C2/m;a=14.913;b=5.778;c=10.979 Å; β=99.58°;Z=2. It crystallizes with a new structure type characterized by three face-shared octahedra. The Ir3O12-groups build up a threedimensional network with an incorporated Ba/O-frame.

Ein neues metastabiles Zinkoxovanadat: Zn4V2O9

For the first time Zn4V2O9 was prepared and investigated by single crystal X-ray methods. The metastable compound exists between a CO2-Laser generated flux and the solid ZnO/V2O5 material. The quenched light brown crystals show a monoclinic symmetry (space group C22—P21,a=10.488 (5),b=8.198 (6),c=9.682 (5) Å; β=118.66 (4)°;Z=4]. Zn4V2O9 has a characteristic Zn/O-framework with incorporated V5+ in tetrahedral coordination. The relationship to Zn4Ta2O9 and the calculation of the madelung part of lattice energy (MAPLE) in respect to the metastable character are discussed.

Ein neuer Strukturtyp mit flächenverknüpften BaO6-Oktaedern: Ba6Nd2Al4O15

SummaryA compound Ba6Nd2Al4O15 with a new structure-type was prepared by solid state reaction. It crystallizes with hexagonal symmetry, space group C6v4 – P 63mc;a=11.5696;c=6.9662 Å;z=2. Ba6Nd2Al4O15 has a dominating Ba/O-framework with incorporated AlO6-octahedra and AlO4-tetrahedra. A main feature of the structure are face connected BaO6-octahedra. One of the point positions of the heavy atoms is occupied statistically by Ba2+ and Nd3+.

Synthese und Strukturuntersuchung von Zn3Ta2O8

Zn3Ta2O8 was prepared by high temperature solid state reaction (CO2-Lasertechnique). X-ray investigations of single crystals yield monoclinic symmetry (a=9.499;b=8.411;c=8.881 Å; β=116.03°, space group C2h6—C2/c). There is no relationship between Zn3Ta2O8 and Zn3Nb2O8. Zn3Ta2O8 shows a characteristic structure type with octahedral coordination of Ta5+ and tetrahedral coordination of Zn2+.

Eine neue Verbindung vom M5TiB2O10-Typ mit geordneter Metallverteilung: Ni5SnB2O10

SummaryThe unknown compound Ni5SnB2O10, prepared by using a flux of excess B2O3, was investigated by single crystal X-ray technique. It crystallizes with orthorhombic symmetry, space group D2h16 — Pnma witha=9.302,b=6.089,c=12.280 Å,Z=4. The mean result of this investigation is a hitherto unobserved strictly ordered metal distribution. Ni5SnB2O10 is not isotypic but related to Ni5TiB2O10.

Ein Beitrag zur Kristallchemie der Kobaltoxoniobate: CoNb2O6 mit Rutilstruktur

CoNb2O6 can be prepared by reaction of stoichiometric amounts of CoO (thermical decomposition of cobaltoxalate) and Nb2O5 in argon-atmosphere up to 1,400 °C. The isolated red-brown single crystals have tetragonal symmetry (a=472.6;c=305.4 pm; space group P42/mnm-D4h14). Electron probe micro-analysis of the single crystals verifies the composition Co0.33Nb0.67O2. Co2+ and Nb5+ occupy statistically the metal positions of the rutil-type structure. The differences between Co0.5Nb0.5O2 (CoNbO4≡AlNbO4-type) and Co0.38Nb0.67O2 (CoNb2O6) are discussed.

Pseudobrookite mit weitgehend geordneter Metallverteilung: CoTi2O5, MgTi2O5 und FeTi2O5

Abstract(A), (B) and (C) were prepared by solid state reactions. Single crystals of quenched samples were examined by X-ray investigation. On the opposite of A2TiO5-pseudobrookite compounds (A), (B) and (C) crystallize with a high ordered metaldistribution on the point positions 4c and 8f.

Synthese und Strukturaufklärung von SrBeLa2O5

A new compound of the formula SrBeLa2O5 was prepared by high temperature technique. Single crystal X-ray investigations led to orthorhombic symmetry (a=9.730,b=7.377,c=6.687 Å, space group: D2h16-Pnma,Z=4). SrBeLa2O5 shows a typical tunnel structure of a three-dimensional connection of Sr, La/O-prisms, related to a distortedKgomé-network. The tunnels are occupied by La3+- and Be2+-ions. A detailed discussion of the polyhedra, their connection, and the statistical distribution of Sr2+ and La3+ within the trigonal O2−-prisms are given.