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1992 (1)
1988 (1)
1Author    Na, Cufef, S. Kummer, W. Massa, D. BabelRequires cookie*
 Title    Zur Struktur der Kupfer-Weberite Na 2 CuCrF 7 Concerning the Structures of the Copper Weberites Na 2 CuCrF 7 and Na 2 CuFeF 7  
 Abstract    The crystal structure of the compound Na 2 CuCrF 7 (orthorhombic, a = 710.0, b = 1033.8, c = 751.8 pm, Z = 4) was refined in space group Pmnb to R (= 0.028 (1545 independent reflections). The Jahn-Teller distortion of the CuF 6 -octahedra (Cu-F = 191.1/193.8/212.4 pm. mean 199.1 pm) reduces the symmetry compared to the body-centered orthorhombic weberite type, to which it is otherwise closely related. The CrF 6 -octahedra. interconnecting parallel chains of CuF 6 -octahedra, are nearly undistorted (mean Cr-F = 190.6 pm). Na 2 CuFeF 7 exhibits a supercell with a different structure (monoclinic, a = 2468.7, b = 734.7, c = 1245.2 pm, ß = 99.29°, Z = 16). It may be interpreted as a new intermediate type between orthorhombic and trigonal weberites. Preliminary results obtained from refinement in space group A2/n (/? g = 0.076) are given and discussed (mean values Cu—F = 199 pm, Fe — F = 192 pm). 
  Reference    Z. Naturforsch. 43b, 694—701 (1988); eingegangen am 9. Februar 1988 
  Published    1988 
  Keywords    Crystal Structure, Weberite, Copper Fluoro Compounds 
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 TEI-XML for    default:Reihe_B/43/ZNB-1988-43b-0694.pdf 
 Identifier    ZNB-1988-43b-0694 
 Volume    43 
2Author    Z. NaturforschRequires cookie*
 Title    Die Kristallstrukturen von N a2CoFeF7 und einer zweiten Modifikation von Na2CuFeF7: Eine weitere Weberit-Variante  
 Abstract    The Crystal Structures o f N a2C o F e F 7 an d a Second M odification o f N a 2C u F e F 7: A n o th e r W eberite V arian t M atth ias W elsch u n d D ietrich Babel* The monoclinic weberites N a2C oF eF 7 (a = 1262.2(10), b = 736.0(4), c = 2451.6(20) pm, ß = 99.71(5)°) and a second modification o f N a 2C uFeF 7 (a = 1244.4(2), b = 734.3(1), c = 2467.2(5) pm, ß = 99.27(3)°), crystallize isotypically in space group C 2 /c, Z = 16. The structure is an intermediate type between orthorhombic and trigonal weberites, characterized by pairs ofpar-allel chains o f octahedra [MF4F2/2]3' (M = Co, Cu) which run in turn along [110] and [110]. The average distances are F e -F = 192 pm in the [FeF6]3~ octahedra o f both compounds. C on­ siderable splitting o f distances occurs in the [CoF6]4-octahedra (av. C o -F = 201 pm), and by Jahn-Teller distortion even more in those o f [CuFJ4-(av. C u -F = 199 pm). One o f the copper surroundings is (pseudo)tetragonally elongated (av sual splitting into three long and three short bonds Some structural relations are discussed. 
  Reference    Z. Naturforsch. 47b, 685—6 (1992); eingegangen am 1. Oktober 1991 
  Published    1992 
  Keywords    Crystal Structure, Weberite, Heptafluorodimetallates(II, III), Jahn-Teller Distortion 
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 TEI-XML for    default:Reihe_B/47/ZNB-1992-47b-0685.pdf 
 Identifier    ZNB-1992-47b-0685 
 Volume    47