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EYPHKAMEN: Ln‐Oktaedertripel in Ln 14 (C 2 ) 3 I 20 mit Ln = La, Ce

2006; Wiley; Volume: 632; Issue: 10-11 Linguagem: Inglês

10.1002/zaac.200500493

1521-3749

Hansjürgen Mattausch, Arndt Simon, Lorenz Kienle, Constantin Hoch, Chong Zheng, Reinhard K. Kremer,

Coordination Chemistry and Organometallics

Abstract EYPHKAMEN: Ln Octahedron Triples in Ln 14 (C 2 ) 3 I 20 with Ln = La, Ce The compounds Ln 14 (C 2 ) 3 I 20 (Ln = La, Ce) are prepared from Ln, LnI 3 , and C molar ratio (11:10:9) at 920 °C (Ce) and 930 °C (La) as pure phases, forming polygonal black crystals with a greenish lustre which are moisture and air sensitive. They are isotypic and crystallize in the triclinic system, $P{\bar 1}$ , with lattice parameters a = 9.761(1) Å, b = 11.790(1) Å, c = 14.055(1) Å, α = 79.60(1)°, β = 71.49(1)°, γ = 65.79(1)° (La 14 (C 2 ) 3 I 20 ) and a = 9.688(1) Å, b = 11.670(1) Å, c = 13.932(1) Å, α = 80.16(1)°, β = 71.81(1)°, γ = 65.88(1)° (Ce 14 (C 2 ) 3 I 20 ). In the crystal structure the Ln atoms form Ln 6 octahedra centered by C 2 ‐groups. Three octahedra are condensed to the triples ((Ln 2 Ln 2 Ln 2/2 C 2 ) 2 (Ln 2 Ln 4/2 C 2 ). The iodine atoms coordinate the octahedra above all free edges as in a M 6 X 12 ‐type cluster. The mean C‐C distance in the C 2 unit is 1.39Å. HRTEM images of crystals selected from different batches prepared at lower temperature show clusters of different lengths besides the triple octahedra. Ce 14 (C 2 ) 3 I 20 is a semiconductor and has an effective magnetic moment of 2.38 μ B .