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Structure determination of KLaS 2 , KPrS 2 , KEuS 2 , KGdS 2 , KLuS 2 , KYS 2 , RbYS 2 , NaLaS 2 and crystal‐chemical analysis of the group 1 and thallium(I) rare‐earth sulfide series
Author(s) -
Fábry Jan,
Havlák Lubomír,
Dušek Michal,
Vaněk Přemysl,
Drahokoupil Jan,
Jurek Karel
Publication year - 2014
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520613034574
Subject(s) - crystallography , crystal structure , thallium , ternary operation , bar (unit) , chemistry , bond length , type (biology) , structure type , materials science , physics , inorganic chemistry , geology , meteorology , computer science , programming language , paleontology
One of the purposes of this work is to provide a crystallographic review of group 1 and thallium rare‐earth ternary sulfides M + Ln 3+ S 2 . We have therefore determined crystal structures of KLaS 2 , KPrS 2 , KEuS 2 , KGdS 2 , KLuS 2 , KYS 2 , RbYS 2 , which belong to the α‐NaFeO 2 structural family (), as well as NaLaS 2 , which is derived from the disordered NaCl structural type (). The determined structures were compared with known members of the group 1 as well as thallium(I) rare‐earth sulfides by the standard tools of crystal‐chemical analysis such as comparison of bond‐valences, analysis of interatomic distances and comparison of the unit‐cell parameters. The results indicate why the cubic structural type is limited to Li + and Na + members of the series only. The analysis has also revealed frequent problems in the reported crystal structures, especially in the determination of the K + compounds, probably due to severe absorption and different accuracy and sensitivity of various instruments. Intense diffuse scattering has been discovered in NaLaS 2 , which will be the subject of further investigation. The newly determined as well as already known structures are summarized, together with critical comments about possible errors in the previous structure determinations.