Sr4Ga3Mo26O48 Containing Mo7 Clusters and Infinite Mo7–Mo10–Mo7 Chains

Abstract

Cs4YbC17site occupancies was attempted. However, this influenced neither the displacement parameters nor the R values. In an attempt to resolve the sixfold disorder, the structure was recalculated based on a triplet of a monoclinic unit cell (a = 9.814, b = 7.634, c = 12.445A, /3 = 108.14 ° , Z = 2) in space group 12/m (t subgroup of R3m). The transformation matrix is i i 1 i ~ l -g,g,Jl,l,0/-?,,~, ~ and the matrix of threefold rotation (twinning element) is 0,1,0/-1,-1,0/0,0,1. However, the refinement did not stabilize and one C1 ion of the YbC16 octahedron showed strongly anisotropic displacement parameters. A further attempt involved refinement as an inversion twin in the space group lm. Anisotropic refinement gave R1 = 0.036 for 1274 reflections with I < 2o'(/) and wR2(all data) = 0.092. The ratio of the triplets was 34(21 + 13):32(30 + 2):34(5 + 29), with the ratios of inversion twins in parentheses. However, the displacement parameters became even more anisotropic and the YbC16 octahedron showed an elongation that we could not rationalize. Furthermore, the R values are no better than in the rhombohedral model. We therefore believe that disorder rather than twinning gives a correct model of the structure.Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994 (Fair, 1990). Program(s) used to solve structure: SHELXS86 (Sheldrick, 1990). Program(s) used to refine structure: SHELXL93 (Sheldrick, 1993). Molecular graphics: ZORTEP (Zsolnai, 1994), SCHAKAL92 (Keller, 1993). Software used to prepare material for publication: SHELXL93.We thank Professor H.-J. Seifert for support and dedicate this paper to him on the occasion of his last 'first fine day'.Lists of structure factors, anisotropic displacement parameters and complete geometry have been deposited with the IUCr (Reference: JZI121). Copies may be obtained through The Managing Editor, International Union of Crystallography, 5 Abbey Square, Chester CH 1 2HU, England. ReferencesBenachenhou, B., Mairesse, G. & Nowogrocki, G. (1986 (Received 29 November 1995: accepted 26 Februar 3' 1996 AbstractThe crystal structure of the strontium gallium molybdate Sr4Ga3M026048 is characterized by quasi-isolated monocapped octahedral M07 clusters and infinite Mo chains arranged in layers parallel to the ac

MTi0.7Mo0.3Mo5O10 (M = Sr, Eu), First Evidence of Mono- and Bicapped Bioctahedral Mo11 and Mo12 Clusters: Synthesis, Crystal Structures, and Physical Properties

“…All reactions were carried out in molybdenum crucibles which were previously cleaned by heating at about 1500 °C for 15 min under a dynamic vacuum of about 10 -5 Torr. Single crystals of EuTi 0.7 Mo 0.3 Mo 5 O 10 were first obtained in an attempt to prepare Eu 4 Ti 3 Mo 26 O 48 which would lead to a compound isostructural with Eu 4 Ga 3 Mo 26 O 48 . The exact composition was first determined by single-crystal X-ray structure investigations.…”

“…Subsequently, both types of clusters were found in well-ordered structures. Thus, the monocapped octahedral Mo 7 has been observed up to now either forming infinite chains with bioctahedral Mo 10 or quasi-isolated in the series of compounds M 4 M‘ 3 Mo 26 O 48 (M = Sr, Eu, M‘ = Al, Ga, Fe) . The bicapped octahedral Mo 8 cluster was encountered in the two isomeric cis and trans forms in the series of polymorphic compounds RMo 8 O 14 (R = La, Ce, Pr, Nd, Sm) compounds that were prepared by high-temperature solid-state reaction.…”

Synthesis, Structural Studies, and Physical Properties of the RE5Mo32O54 (RE=La, Ce, Pr, Nd) Compounds Containing trans-Bicapped Mo8 Octahedral Clusters and Mo7–Mo10–Mo7 Triclusters

“…The second one is built up from one Mo and two Mo clusters interconnected through short Mo}Mo bonds of about 2.77 A s and was observed in coexistence with bicapped octahedral Mo clusters in La Mo O (16). The tricluster Mo }Mo }Mo thus formed also constitutes the repeat unit of the in"nite chain found in the quaternary M M Mo O (M"Sr, Eu; M"Al, Fe, Ga) compounds (17,18). The interest of this class of compounds with high nuclearity Mo clusters not only resides in their fascinating structural aspects but also in the various electrical and magnetic properties they exhibit.…”

The cluster compound In4Ti1.5Mo0.5Mo14O26 containing Mo14 clusters and the new mono- and bi-capped trioctahedral Mo15 and Mo16 clusters: Synthesis, crystal structure, and electrical and magnetic properties

“…Subsequently, the Mo 7 and Mo 8 clusters were found in well-ordered structures. The monocapped octahedral Mo 7 unit has been observed up to now either forming infinite chains with bioctahedral Mo 10 unit or quasi-isolated in the series of compounds M 4 M' 3 Mo 26 O 48 (M = Sr, Eu, Mo'= Al, Ga, Fe) [18]. The bi-capped octahedral [20].…”