AbstractFor Abstract see ChemInform Abstract in Full Text.

At orthorhombic single crystals of Pb4Sr2Fe6O15 (a = 568.73(8), b = 392.03(4), c = 2107.5(3) pm; Z = 4/3, space group Pnma) a X-ray structure determination has been performed (R-1 = 0,036 for 488 ''observed'' resp. wR(2) = 0,073 for all 643 independent reflexions). It revealed a framework of polyhedra related to perovskite, in which chains of edge sharing pyramids [FeO5] (average Fe1-O: 197 pm; Fe1-Fe1: 305.5 pm) are linked via apices with corner-sharing [FeO6] octahedra (Fe2-O: 201 pm). 12-fold, strongly distorted cuboctahedrally coordinated ''perovskite positions'' show mixed occupancy by 2/3 Sr + 1/3 Pb (= Sr2; Sr2-O: 287 pm). More spacy channels, running parallel to the chains of pyramids along [010] of the structure, contain lead atoms only. The double occupancy of the corresponding cages results in short distances Pb1-Pb1 (355.9 pm) and Pb1-Fe2 (314.4 pm), as well as in a very asymmetric [PbO6] coordination (Pb1-O: 253 pm), in the opposite hemisphere of which the lone electron pair s(2) is supposed to be located. Details are communicated and structural relations discussed.

Based on newly measured X-ray single crystal data the crystal structures of the orthorhombic fluoroperovskites NaMF3 (M = Mg, Co, Ni, Zn) were refined in space group Pbnm (GdFeO3 type, Z = 4). The octahedra are but slightly distorted; the average distances (and bridge angles M-F-M) are: Mg-F = 197.8 pm (150.9-degrees), Co-F = 203.8 pm (146.1-degrees), Ni-F = 200.3 pm (148.0-degrees) and Zn-F = 202.3 pm (147.4-degrees). With respect to the axes of the pseudocell (Z = 1) the octahedra are rotated by tilt angles which vary, including NaMnF3 and NaFeF3, between 14.6 and 18.8-degrees. The tilting becomes the more pronounced, the smaller the tolerance factor of the compound, so as to yield uniformly average values of Na-F = 232 pm for the four shortest distances within the [NaF8] coordination (distorted tetrahedron and bi-capped trigonal prism, respectively). Measurements of magnetic powder susceptibilities show that tilting of octahedra is no sufficient cause to produce spin canting resulting in ferromagnetism: This property is confirmed only for NaNiF3 (T(N) = 150 K), whereas NaCoF3 exhibits a sharp minimum in its chi-1-T curve (T(N) = 75 K) and remains uncanted antiferromagnetic then down to 4.2 K.

The crystal structures of four compounds Cs4M3F10 (M = Mg, Co, Ni, Zn), isotypic with orthorhombic Ba4(Ti,Pt)3O10, space group Cmca, Z = 4, were refined to wR < 0.05 using some 1200 single crystal reflections. There are trinuclear groups [M3F12] of face-sharing octahedra in the structure two-dimensionally connected via terminal corners to form a zig-zag layer. The M-M distances within the [M3F12] unit are enlarged for the closed shell ions (Mg-Mg: 274.8, Zn-Zn: 279.4 pm), if compared with the even larger ions with partly filled d shell (Ni-Ni: 272.7, Co-Co: 277.9 pm). The resulting average distances M-F agree well with those of corresponding fluorides also containing face-sharing octahedra (M = Mg: 200.9, Co: 205.7, Ni: 202.8, Zn: 205.1 pm). The magnetic powder susceptibility of Cs4Ni3F10 has been studied down to liquid helium temperature. The compound is antiferromagnetic at 4.2 K, but within a sharp temperature range of 9.5 < T < 21 K it exhibits a small spontaneous magnetization. The disappearance of this spontaneous magnetization at T(N) almost-equal-to 9 K is interpreted as the Neel temperature, where three-dimensional magnetic order sets in.

AbstractDie tetragonalen Bis(‐tetramethylammonium)‐Alkali‐Hexacyanometallate [N(CH3)4]2KMn(CN)6 (a = 884.8(2), c = 1222,2(6) pm) und [N(CH3)4]2RbCo(CN)6 (a = 884,7(1), c = 1233,1(2) pm) wurden in Form von Einkristallen dargestellt und röntgenographisch ihre Strukturen bestimmt (wR = 0,050 bzw. 0,047 für 486 bzw. 463 unabhängige Reflexe; Raumgruppe 14/m, Z = 2). Die mittleren Abstände in der resultierenden Elpasolithstruktur, die durch geringe ferrorotative Drehung der [M(CN)6]3−‐Oktaeder nur wenig tetragonal verzerrt ist (MnC = 201,8, CN = 115,6, KN = 307,1 pm bzw. CoC = 190,7, CN = 114,8, RbN = 320,1 pm), erscheinen leicht vergrößert im Vergleich zu Werten die in verwandten Cyanokomplexen beobachtet wurden. Gründe dafür werden im Rahmen einer Toleranzfaktorbetrachtung für Cyano‐Elpasolithe diskutiert.

Six compounds have been prepared and their single crystals studied: Ba2RbFe2F9, Ba2CsCo2F9, Ba2ANi2F9 (A = K, Rb, Cs) and Ba2CsZn2F9. They are isostructural with Ba3Re2O9, space group R3mBAR, Z = 3, with cell dimensions of about a = 590, c = 2100 pm. Full X-ray structure refinements (wR < 0.04) yielded the average distances Fe-F = 206.4, Co-F = 205.1, Ni-F = 201.6 and Zn-F = 204.3 pm. However, pronounced splitting (5...9%) is observed into 3 long bridging and 3 short terminal bonds. The resulting honeycomb layer structure [MF3F3/2]2.5- of fac-corner-sharing octahedra is discussed along with relations to hexagonal perovskites 9L-CsCoF3, 2L-CsNiF3 and dinuclear Cs3Fe2F9.

At single crystals of Sr5Fe3F19 a X-ray structure determination in the tetragonal space group 14/m was performed (a = 1429.4(3), c = 730.7(3) pm; Z = 4. wR = 0.019 for 502 independent reflections). Within the structure there are isolated, but disordered dimeric anion groups of edge-sharing octahedra [Fe2F10]4- (average Fe-F = 193.3 pm, Fe-Fe = 319.1 pm). They are embedded in a framework of strontium ions (C.N. 8-10) and single FeF6(3-) octahedra (Fe-F = 191.0 resp. 192.7 pm, if corrected for thermal motion). The strong relations to the crystal structure of BaTiF5 and to further related fluoride compounds are discussed.

AbstractDie Kristallstrukturen des triklinen NaCuF3 (a = 539,1, b = 555,2, c = 792,8 pm, α = 90,66, β = 92,05, γ = 86,95°; P1, Z = 4) und des tetragonalen, mit KCuF3 isotypen RbCuF3 (a = 602,3, c = 791,2 pm; I4/mcm, Z = 4) wurden röntgenographisch bestimmt und auf wR = 0,038 (2113 Reflexe) bzw. 0,039 (257 Reflexe) verfeinert. Die Strukturen leiten sich vom orthorhombischen (GdFeO3‐) bzw. kubischen Perowskit‐Typ durch Jahn‐Teller‐Verzerrung ab. Die in beiden Verbindungen unterschiedlich gestreckten CuF64−‐Oktaeder (Mittelwert NaCuF3: CuF = 188,9/197,3/225,6(2) pm; RbCuF3: 188,3/197,8/237,6(3) pm) sind nach demselben Muster antiferrodistortiv geordnet, jedoch unter Winkelung CuFCu = 144,2…︁148,0(1)° in NaCuF3. Strukturelle Beziehungen zu den genannten Prototypen und zu vergleichbar Jahn‐Teller‐verzerrten Kupfer‐Fluorverbindungen werden diskutiert.

(1) Rb 2 FeF 5 cristallise dans Pnma avec a=756,5, b=581,0, c=1200,2 pm, z=4, affinement jusqu'a Re 0,025. (2) (CH 3 NH 32 FeF5 cristallise dans Pnma avec a=935,7, b=789,6, c=1017,2 pm, z=4, affinement jusqu'a R=0,029. Un compose (1), de structure identique a Rb 2 CrFe 5 , presente des octaedres connectes de facon cis. (Fe-F=189,2 a 204,4 pm. Fe-F-Fe=180°). Dans le compose (2), de structure relative a la structure type (NH4)MnFe 5 , les octaedres sont connectes de facon trans (Fe-F=190,7 a 191,4 pm. F-Fe-F.164,0°). Ces differences et l'influence des liaisons hydrogene sont discutees

AbstractSingle crystals of NaCuF3 and RbCuF3, obtained by solid‐state reaction from the binary fluorides, belong to the triclinic space group P1, Z=4 and to the tetragonal space group I4/mcm, Z=4, respectively.

AbstractRb2FeF5 (I) is prepared by solid state reaction of the binary fluorides at 850 °C. Single crystals are obtained from the powdered product by hydrothermal treatment (43% HF, 30 kbar, 250 °C).

AbstractThe title compounds are prepared by solid state reaction of NaF, CuF2, and CrF3 and FeF3, resp. (closed Au‐crucible, 750‐800 °C, 12 h).

Le compose Na 2 CuCrF 7 cristallise dans le systeme orthorhombique avec le groupe d'espace Pmmb et sa structure est affinee jusqu'a 0,0265. Le compose Na 2 CuFeF 7 cristallise dans le systeme monoclinique avec le groupe d'espace A2/n et sa structure est affinee jusqu'a 0,0265

AbstractThe parameters of the cubic elpasolite structure (space group Fm3m, Z=4) of the metastable title compounds have been determined by single‐crystal X‐ray diffraction.

Looking for compounds Cs2MF4 the cesium richest composition we found at M(II) = Co, Ni was Cs7M4F15. X-ray single crystal work revealed a layer structure (P21/c, Z=2), built up from face-sharing double octahedra M2F9 which are mutually connected via three of their vertices. Some interatomic distances are given in Table I, along with data of six novel compounds Ba2AM2F9 (R3m, Z=3). The puckered layer structure of the latter consists of single octahedra, sharing three corners in a fac-position. It derives from the hexagonal perovskite structure of CsCoF3 by omitting the central cations within the groups of three face-sharing octahedra.