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Pr 2 Br 5 : No mixed valence praseodymium bromide
Author(s) -
Schleid Thomas,
Meyer Gerd
Publication year - 1987
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.19875520910
Subject(s) - praseodymium , isostructural , monoclinic crystal system , tribromide , crystallography , chemistry , valence (chemistry) , trigonal crystal system , metal , crystal structure , bromide , inorganic chemistry , organic chemistry
The metallothermic reduction of praseodymium tribromide, PrBr 3 , with lithium metal (molar ratio 1:1) in sealed tantalum containers at 850°C yields bronze lustrous rods of Pr 2 Br 5 . The crystal structure (monoclinic, P2 1 /m, Z = 2, a = 774.38(4), b = 415.33(3), c = 1327.06(9) pm, β = 90.816(6)°, V m = 128.52(2) cm 3 mol −1 ) contains seven‐ and eight‐coordinate trivalent praseodymium in mono‐ and bicapped trigonal prisms. Pr 2 Br 5 should therefore be formulated as (Pr 3+ ) 2 (Br − ) 5 (e − ). It is isostructural with Pr 2 I 5 and is believed to be identical with PrBr 2,38 reported for the Pr/PrBr 3 system.