NEW LANTHANIDE SELENOPHOSPHATES - INFLUENCE OF FLUX COMPOSITION ON THE DISTRIBUTION OF [PSE4](3-) [P2SE6]4(-) UNITS AND THE STABILIZATION OF THE LOW-DIMENSIONAL COMPOUNDS A(3)REP(2)SE(8), AND A(2)(RE)P2SE7 (A = RB, CS RE = CE, GD)/
K. Chondroudis et Mg. Kanatzidis, NEW LANTHANIDE SELENOPHOSPHATES - INFLUENCE OF FLUX COMPOSITION ON THE DISTRIBUTION OF [PSE4](3-) [P2SE6]4(-) UNITS AND THE STABILIZATION OF THE LOW-DIMENSIONAL COMPOUNDS A(3)REP(2)SE(8), AND A(2)(RE)P2SE7 (A = RB, CS RE = CE, GD)/, Inorganic chemistry, 37(15), 1998, pp. 3792-3797
The reaction of Ce or Gd with a molten mixture of A(2)Se/P2Se5/Se (A =
Rb, Cs) produced the quaternary compounds Rb3CeP2Se8 (I) and Cs3GdP2S
e8 (II), as well as Rb2CeP2Se7 (III) and Rb2GdP2Se7 (IV). The orange c
rystals of I, II and the red crystals of III, IV are air- and water-se
nsitive. Compounds I, II crystallize in the monoclinic space group P2(
1)/c, and for I, a = 9.6013(2) Angstrom, b = 18.0603(1) Angstrom, c =
10.0931(1) Angstrom, beta = 90.619(1)degrees, and Z = 4. Compounds III
, IV crystallize in the monoclinic space group P2(1)/n, and for IV, a
= 10.137(2) Angstrom, b = 7.212(1) Angstrom, c = 20.299(2) Angstrom, b
eta = 98.23(1)degrees, and Z = 4. Compounds I, II have a 1-D structure
with [(RE)P2Se8](n)(3n-) chains separated by A(+) cations. The RE3+ l
anthanide cation is in a bicapped trigonal prismatic coordination with
four tridentate [PSe4](3-) ligands. Compounds III, IV possess a 2-D s
tructure. Each layer consists of [RE(PSe4)](x) ''chains'' interstitche
d in two dimensions by hexadentate [P2Se6](4-) ligands. The trivalent
RE cation is in a square antiprismatic coordination. The compounds wer
e characterized with differential thermal analysis, far-IR, and solid-
state UV/vis diffuse reflectance spectroscopy. Magnetic measurements i
ndicate that the compounds obey the Curie law with mu(eff) values clos
e to those of the free RE3+ ions.