Record details

Title
    Refinement of the Crystal Structure of Cronstedtite-1T
Statement of responsibility
    Jiří Hybler, Václav Petříček, Slavomil Ďurovič, Lubomír Smrčok
Author
    Ďurovič, Slavomil
    Hybler, Jiří
    Petříček, Václav
    Smrčok, Lubomír
Language
    anglicky
Source title - serial
    Clays and clay minerals
Vol./nr.
    Vol. 48, no. 3
Pages
    p. 331-338
Year
    2000
Notes
    1 obr., 5 tab., 2 s.bibl.
    il.
    Zkr. název ser.: Clays and Clay Miner.
Subject group
    cronstedtit
    fylosilikáty
    krystalová struktura
    polytypie
    zpřesňování struktury
Geographical name
    Chvaletice (Pardubice)
    ČR-Čechy
    Litošice (Pardubice)
    Rumunsko
    Slovensko
    SRN-Sachsen-Anhalt
    Velká Británie-England
Keyword
    Cronstedtite-1T
    Crystal
    Refinement
    Structure
Abstract (in english)
   The crystal structure of cronstedtite-1T was refined in space group P31m, using two crystals: a triangular tabular crystal from Herja, Romania and a conical crystal from Lostwithiel, Cornwall, England. The Herja sample has the compositon of (Fe2+2.20Fe3+0.80) (Si1.20Fe3+0.78Al0.02)O5(OH)4 and the Lostwithiel sample has the composition of (Fe2+2.32Fe3+0.68) (Si1.32Fe3+0.66Al0.02)O5(OH)4. The resutls of refinements are as follows: a=5.512(1) A, c=7.106(1) A, R=3.07% and 342 independent reflections: and a=5.503(1), c=7.104(1) A, R=2.24% and 335 independent reflections for the Herja and Lostwithiel samples respectively. The structure consists of one tetrahedral and one octahedral sheet. There is one octahedral site, M1, occupied by Fe only, and one tetrahedral site, T1, occupied by Si and Fe in the ratio of 0.617(8):0.383 (Herja) and 0.699(6):0.301 (Lostwithiel). Positions of two hydrogen atoms were determined from a difference map for the Lostwithiel data.
   The ditrigonalization angle of the tetrahedral sheet is Ó=-11,5° (Herja) and Ó=-11.1° (Lostwithiel), and the structures have a Franzini-layer type of B. The crystals studied are affected by ˝b/3 stacking faults which produced slight streaking of h - kě3n reflections
Contributor
    Česká geologická služba
Contributor code
    ČGS (UNM)
Source format
    U
Entered date
    5. 10. 2007
Import date
    8. 8. 2012