A NEW RARE-EARTH-METAL NITRIDE HALIDE WITH UNUSUAL STRUCTURAL FEATURES - CSXNA1-XLA9I16N4 WITH A REMARK ABOUT THE STOICHIOMETRIC COMPOUNDS ALA(9)I(16)N(4) (A=NA, RB, CS)

Citation
M. Lulei et Jd. Corbett, A NEW RARE-EARTH-METAL NITRIDE HALIDE WITH UNUSUAL STRUCTURAL FEATURES - CSXNA1-XLA9I16N4 WITH A REMARK ABOUT THE STOICHIOMETRIC COMPOUNDS ALA(9)I(16)N(4) (A=NA, RB, CS), European journal of solid state and inorganic chemistry, 33(2-3), 1996, pp. 241-250
Citations number
26
Categorie Soggetti
Chemistry Inorganic & Nuclear
ISSN journal
09924361
Volume
33
Issue
2-3
Year of publication
1996
Pages
241 - 250
Database
ISI
SICI code
0992-4361(1996)33:2-3<241:ANRNHW>2.0.ZU;2-O
Abstract
Reactions of LaI3, CsI and NaN3 in niobium tubes at 750 degrees C yiel ded pale yellow, transparent crystals of CsxNa1-xLa9I16N4 (x = 0.64) w hich were examined by single crystal X-ray diffraction and EDX. The st ructure (orthorhombic, Fddd, Z = 8, a = 8.980(4) Angstrom, b = 22.91(2 ) Angstrom, c = 43.61(3),Angstrom, R(F) = 0.023, R(w) = 0.031) contain s infinite chains of nitrogen centered, edge-sharing La-4 tetrahedra a s well as seperate lanthanum atoms that interconnect the chains via co mmon iodine atoms. The result is a lanthanum-nitrogen-iodine framework with the alkali-metal atoms statistically distributed on sites within channels in the structure. Preliminary experiments with the exact sto ichiometry ALa(9)I(16)N(4) (A = Na, Rb or Cs) and only one alkali meta l also yielded the same structure type according to the powder pattern s. The compound is related to the Gd2Cl3N structure type and also to ' 'reduced'' cluster compounds like Pr5I4Ru but with a new type of conne ctivity.