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Three Bromides of Lanthanum: LaBr 2 , La 2 Br 5 , and LaBr 3
Author(s) -
Krämer Karl,
Schleid Thomas,
Schulze Mathias,
Urland Werner,
Meyer Gerd
Publication year - 1989
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19895750109
Subject(s) - lanthanum , tribromide , monoclinic crystal system , ammonium bromide , chemistry , hexagonal crystal system , tantalum , bromide , crystallography , crystal structure , inorganic chemistry , nuclear chemistry , organic chemistry , pulmonary surfactant , biochemistry
Colourless LaBr 3 was obtained via the ammonium‐bromide route and in singlecrystalline form by chemical vapour‐phase transport with aluminium tribromide. Black single crystals of LaBr 2 and La 2 Br 5 have been grown from the melts that are obtained by lithium reduction of lanthanum tribromide in sealed tantalum ampoules at 850°C. The crystal structures of the three bromides of lanthanum were refined: LaBr 2 . 2H 2 –MoS 2 type, hexagonal (P6 3 /mmc), a = 409.88(4) pm, c = 1390.0(1) pm, R = R w = 0.092; La 2 Br 5 . Pr 2 I 5 type, monoclinic (P2 1 /m), a = 789.09(6) pm, b = 424.89(4) pm, c = 1342.3(1) pm, β = 91.60(1)º, R = 0.067, R w = 0.055; LaBr 3 . UCl 3 type, hexagonal (P6 3 /m), a = 797.13(4) pm, c = 452.16(4) pm, R = 0.036, R w = 0.032.