Nouvelle serie d'oxydes derives de la structure de α-U3U8: MIIUMo4O16
1987; Elsevier BV; Volume: 67; Issue: 2 Linguagem: Francês
10.1016/0022-4596(87)90376-8
ISSN1095-726X
Autores Tópico(s)Nuclear Materials and Properties
ResumoA new family of isotypical oxides MIIUMo4O16 (MII = Mg,Mn,Cd,Ca,Hg,Sr,Pb) is identified. The structure of the compound with Ca was determined by X-ray diffraction. It is triclinic, space group P1 with a = 13.239(5) Å, b = 6.651(2) Å, c = 8.236(3) Å, α = 90°00(4), β = 90°38(4), γ = 120°16(3), Z = 2. The final index and the weighted Rw index are 0.049 and 0.040, respectively. The cell is related to the orthorhombic one of α-U3O8: a = 2a0, b = −(a0 + b0)/2, c = 2c0. The structure, reminiscent of that of α-U3O8, consists of chains of [Ca,U]O7 pentagonal bipyramids and MoO6 octahedra, running parallel to the c axis. The UO distances along the UOCaO chains are shortened to 1.77(1) Å. The uranyl ion was characterized by its IR spectrum. Une nouvelle famille d'oxydes isotypes MIIUMo4O16 (MII = Mg,Mn,Cd,Ca,Hg,Sr,Pb) est mise en évidence. La structure du composé au calcium est déterminée par diffraction X: maille triclinique centrée, a = 13,239(5) Å, b = 6,651(2) Å, c = 8,236(3)Å, α = 90°00(4), β = 90°38(4), γ = 120°16(3), Z − 2. Le facteur résiduel est égal à 0,049 et le facteur pondéréà 0,040. La maille est en relation avec celle de α-U3O8: a = 2a0, b = −(a0 + b0)/2, c = 2c0. La structure apparentée à celle α-U3O8, consiste en chaines de bipyramides pentagonales [Ca,U]O7 et d'octaèdres MoO6, parallèlement àc. Les distances UO dans les chaines UOCaO sont égales à, 1,77(1) Å. L'ion UO2+2 est caractérisé par son spectre IR.
Referência(s)