Nonstoichiometric REEAl2.07(B4O10)O0.60(REE=(La, Ce); Ce; Nd) dimetaborates have been crystallized and analyzed by means of single crystal X-ray diffraction. The compounds resulted to be isostructural within hexagonal space group P62m (n. 189), with the following unit cell parameters: a = 4.6060(6) Å, c = 9.3510(8) Å and V = 171.81(3) Å3 (La, Ce); a = 4.5960(6) Å; c = 9.3170(10) Å and V = 170.44(4) Å3 (Ce); a = 4.5830(7) Å, c = 9.2810(14) Å and V = 168.82(4) Å3 (Nd). The REE cations are surrounded by six oxygen atoms, making up a trigonal prismatic coordination; Al cation is surrounded by five oxygen atoms, resembling a square pyramidal coordination, while the BO4 group displays tetrahedral arrangement. The three-dimensional framework can be described as a mica-like structure packed down crystallographic axis c, with layers of six-membered rings of B tetrahedra alternated by inter-layers REE cations and layers of Al polyhedra. A complex network of REE...O and Al...O interactions concur to stabilize the framework.
Capitelli, F., Chita, G., Leonyuk, N.i., Koporulina, E.v., Bellatreccia, F., DELLA VENTURA, G. (2009). X-ray crystal structure of synthetic REEAl<sub>2.07</sub>(B<sub>4</sub>O<sub>10</sub>)O<sub>0.60</sub> (REE = (La, Ce); Ce; Nd) dimetaborates. ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 224, 478-483.
X-ray crystal structure of synthetic REEAl2.07(B4O10)O0.60 (REE = (La, Ce); Ce; Nd) dimetaborates
BELLATRECCIA, FABIO;DELLA VENTURA, Giancarlo
2009-01-01
Abstract
Nonstoichiometric REEAl2.07(B4O10)O0.60(REE=(La, Ce); Ce; Nd) dimetaborates have been crystallized and analyzed by means of single crystal X-ray diffraction. The compounds resulted to be isostructural within hexagonal space group P62m (n. 189), with the following unit cell parameters: a = 4.6060(6) Å, c = 9.3510(8) Å and V = 171.81(3) Å3 (La, Ce); a = 4.5960(6) Å; c = 9.3170(10) Å and V = 170.44(4) Å3 (Ce); a = 4.5830(7) Å, c = 9.2810(14) Å and V = 168.82(4) Å3 (Nd). The REE cations are surrounded by six oxygen atoms, making up a trigonal prismatic coordination; Al cation is surrounded by five oxygen atoms, resembling a square pyramidal coordination, while the BO4 group displays tetrahedral arrangement. The three-dimensional framework can be described as a mica-like structure packed down crystallographic axis c, with layers of six-membered rings of B tetrahedra alternated by inter-layers REE cations and layers of Al polyhedra. A complex network of REE...O and Al...O interactions concur to stabilize the framework.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
