Synthesis and structure of LaMo7.70O14, a novel compound containing an Mo8 cluster

The modulated structure of LaMo8O14

“…All the reflections conform to mmm Laue symmetry. As suggested by the study of the main reflections, the basic structure of this crystal, having the composition LaMosO~4, appears to be closely related to the structure of the orthorhombic crystal of composition LaMo7.70]4 (Leligny et al, 1990). Indeed, for the two phases, the lattice parameters are similar [aM = 11.129 (1), bM = 10.000 (1), cM = 9.218 (1), a = 11.171 (1), b = 9.985 (1), c= 9.196 (1)A, where M refers to the modulated crystal].…”

“…So far as we are aware, the cis-edge-sharing isomer has been observed in chemical systems only for LnMosyOl4 (Ln = Ce, La, Pm, Nd, Gd) (Leligny et al, 1990;Gougeon & McCarley, 1991). On the other hand, the trans isomer of the metal cluster has been observed in certain coordination complexes such as Re8C(CO)24 (Ciani, D'Alfonso, Freni, Romiti & Sironi, 1982).…”

Structure of La5Mo32O54 containing trans bicapped Mo8 octahedral clusters and tricluster Mo7–Mo10–Mo7 chain fragments

“…It constitutes the second example of the Mo8-type cluster found in reduced molybdenum oxides. Indeed, the first example, which corresponds to the cis-edge-shared form, has recently been observed in the series RMo80~4 (R=La, Ce, Pr, Nd, Sm) (Leligny et al, 1990;Gougeon & McCarley, 1991 (Lii, Wang & Wang, 1988) and between the MOlo clusters in MMo508. The MOT cluster is new to reduced molybdenum oxides and is formed by capping one face of a distorted octahedron.…”

“…Up to now, this study has led to the synthesis of six new structure types by solid-state reaction: LaaMo2Oll (Gall & Gougeon, 1992) including isolated Mo2 dimers, RMosOl4 (R=La, Ce, Pr, Nd, Sm) (Leligny, Ledesert, Labbe, Raveau & McCarroll, 1990;Gougeon & McCarley, 1991) comprising Mo8 clusters, R16M021056 (R = La, Ce, Pr, Nd) (Gall & Gougeon, 1993) showing isolated MOlo clusters, RMosO8 (R = La, Ce, Pr, Nd, Sm, Eu, Gd) (Hibble, Cheetham, Bogle, Wakerley & Cox, 1988;Gougeon, Gall & Sergent, 1991;Gall, 1990) containing chains of bioctahedral Molo clusters, R4Mo4Oll (R =Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) (Gougeon, Gall & McCarley, 1991a) characterized by infinite chains of trans-edge-shared Mo6 octahedra, and R4Mo18032 (R = Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) (Gougeon, Gall & McCarley, 1991b) The basic building blocks of LasMo32054 are the new M08 cluster and the novel M024 tricluster chain fragment, shown in Fig. 1 with their oxygen environments.…”

Crystal Structure of BaNb6.3(1)Ti3.6(1)O16 containing Nb6O12, fused Ti3O13 Clusters and Ti3O10 Units

“…The oxo-molybdates to some extent exhibit a broader variation of clusters, such as Mo 3 O 13 units in Zn 2 Mo 3 O 8 [6], Mo 4 [7], Mo 8 [8] and Mo 10 units [9,10]. The discrete Mo 6 O 12 O 6 cluster is only found in Ca 16.5 Mo 13.5 O 40 [11] and LaMo 2 O 5 [12], while condensation via edge sharing frequently occurs, yielding the infinite chains in NaMo 4 O 6 [13] and the oligomeric units in indium oxo-molybdates [3].…”