ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Language
Number of Hits per Page
Default Sort Criterion
Default Sort Ordering
Size of Search History
Default Email Address
Default Export Format
Default Export Encoding
Facet list arrangement
Maximum number of values per filter
Auto Completion
Topics (search only within journals and journal articles that belong to one or more of the selected topics)
Feed Format
Maximum Number of Items per Feed
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 0044-2313
    Keywords: Sodium trifluorometallates ; fluoroperovskites ; crystal structure ; tolerance factor ; antiferromagnetism ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure Refinements of Sodium Trifluorometallates NaMF3 (M = Mg, Co, Ni, Zn): Tilting of Octahedra and Tolerance Factor of Orthorhombic FluoroperovskitesBased 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°), Co—F = 203.8 pm (146.1°), Ni—F = 200.3 pm (148.0°) and Zn—F = 202.3 pm (147.4°). 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°. 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 bicapped 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 (TN = 150 K), whereas NaCoF3 exhibits a sharp minimum in its χ-l-T curve (TN = 75 K) and remains uncanted antiferromagnetic then down to 4.2 K.
    Notes: Auf der Basis neu gemessener röntgenographischer Einkristalldaten wurden die Kristallstrukturen der orthorhombischen Fluorperowskite NaMF3 (M = Mg, Co, Ni, Zn) in der Raumgruppe Pbnm verfeinert (GdFeO3-Typ, Z = 4). Die Oktaeder sind kaum verzerrt; die mittleren Abstände (und Brückenwinkel M—F—M) betragen: Mg—F = 197,8 pm (150,9°), Co—F = 203,8 pm (146,1°), Ni—F = 200,3 pm (148,0°) und Zn—F = 202,3 pm (147,4°). Unter Einbeziehung von NaMnF3 und NaFeF3 ergeben sich von 14,6 bis 18,8° variierende Kippungswinkel der Oktaeder gegen die Achsen der Pseudozelle (Z = 1). Die Oktaeder sind um so stärker gekippt, je kleiner der Toleranzfaktor der Verbindungen ist, so daß einheitlich ein Mittelwert von Na—F = 232 pm für die vier kürzesten Abstände innerhalb der [NaF8]-Koordination resultiert (verzerrtes Tetraeder bzw. zweifach überkapptes trigonales Prisma). Messungen der magnetischen Pulversuszeptibilität zeigen, daß die Oktaederkippung kein ausreichender Grund für Spinverkantung und daraus resultierenden Ferromagnetismus ist: Dieser kann nur für NaNiF3 (TN = 150 K) bestätigt werden, während NaCoF3 ein scharfes Minimum in der χ-1-T-Kurve zeigt (TN = 75 K) und dann bis herab zu 4,2 K unverkantet antiferromagnetisch bleibt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...