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Synthesis, Crystal Structures and Properties of the First Lanthanum Selenide Chlorides, LaSeCl and La 3 Se 4 Cl
Author(s) -
Schurz Christian M.,
Frunder Susanne,
Schleid Thomas
Publication year - 2013
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201300138
Subject(s) - chemistry , selenide , crystallography , lanthanum , octahedron , selenium , crystal structure , trigonal crystal system , inorganic chemistry , organic chemistry
The first two lanthanum selenide chlorides, LaSeCl and La 3 Se 4 Cl, both crystallize orthorhombically in space group Pnma (no. 62). They emerged from reactions of LaCl 3 with lanthanum and selenium in appropriate molar ratios at 800–900 °C. Single crystals of the yellow LaSeCl adopt the cotunnite‐type structure of PbCl 2 with a = 760.63(5), b = 433.52(3) and c = 910.07(6) pm ( Z = 4). The tricapped trigonal prisms [LaSe 5 Cl 4 ] 11– share their triangular faces to form chains that run parallel to the [010] direction and are condensed through caps and common edges to give a complete crystal structure in accord with ∞ 3 {LaSe 5/5 Cl 4/4 }. Dark‐red La 3 Se 4 Cl exhibits the U 3 S 5 ‐type structure with a = 1271.98(5), b = 855.84(3) and c = 795.05(2) pm ( Z = 4). The chloride anions are located at the Wyckoff position 8 d together with selenium showing site occupation factors of 0.5 for both anion types. Bicapped trigonal prisms [LaSe 7 Cl] 12– with (La2) 3+ are connected through common faces and corners to form a three‐dimensional framework suited to the embedding of chains of fused tricapped trigonal prisms [LaSe 5+ 1 Cl 2 ] 11– with (La1) 3+ running parallel to [010]. The absorption edge energy of approximately 1.75 eV indicates a wide band‐gap semiconductor that is stable towards air, water and some aqueous bases at different concentrations.