Podrobnosti záznamu

Název
    Crystal structure, cation ordering and polytypic character of diaphorite, Pb2Ag3Sb3S8, a PbS-based structure
Údaj o odpovědnosti
    Thomas Armbruster, Emil Makovický, Peter Berlepsch, Jiří Sejkora
Autor
    Armbruster, Thomas
    Berlepsch, Peter
    Makovický, Emil
    Sejkora, Jiří, 1968-
Jazyk
    anglicky
Zdrojový dokument - seriál
    European journal of mineralogy
Svazek/č.
    Vol. 15, no. 1
Strany
    p. 137-146
Rok
    2003
Poznámky
    5 obr., 7 tab., 16 bibl.
    il.
    Zkr. název ser.: Eur. J. Mineral.
Předmětová skupina
    antimon
    krystalová struktura
    olovo
    polytypie
    stříbro
    stupeň uspořádanosti
    substituce
    sulfosoli
Geografické jméno
    ČR-Čechy
    Příbram
Klíčové slovo
    Cation
    Character
    Crystal
    Diaphorite
    Ordering
    Pb2Ag3Sb3S8
    PbS-based
    Polytypic
    Structure
Abstrakt (anglicky)
   he crystal structure of diaphorite, Pb2Ag3Sb3S8, from hydrothermal veins at Příbram in central Bohemia (Czech Republic) was solved and refined from X-ray data of a crystal twinned by pseudo-merohedry. Diaphorite is rnonoclinic, space group P2l/c, a = 17.852(4), b = 5.887(1), c = 15.809(3) A and |3 = beta116.17(3)° ,Z=4,ró = 6.06 g/cm3. The structure can be derived from the one of galena, PbS, by the substitution Ag+ + Sb3+ <- 2 Pb2+. In addition to eight S, three Sb, two Ag, and one Pb positions, the average structure exhibits also two mixed (Pb2+, Ag+) sites (Ml, M2). The different coordination requirements for Pb2+ and Ag+ make a complete miscibility between these ions rather unlikely. The observed structure is a family or superposition structure and four possible, maximally Pb2+, Ag+ ordered structures can be derived with space-group symmetries (la): PI, (Ib) and (2a): P21ln, and (2b): P2,.
   The structures (la) and (2b) have the same cell dimensions as the family structure whereas structures (Ib) and (2a) have a doubled a periodicity compared to the family structure. In addition, each of the above space groups gives rise to two different configurational variants depending on the spatial relation of homoionic occupied M1 and M2 sites
Přispěvatel
    Česká geologická služba
Kód přispěvatele
    ČGS (UNM)
Zdrojový formát
    U
Datum vložení
    15. 8. 2007
Datum importu
    8. 8. 2012