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.

Philippe Gall (1) , Thierry Guizouarn (1) , Patrick Gougeon (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

Single crystals of the new quaternary compd. In4Ti1.5Mo0.5Mo14O26 were obtained by solid state reaction. The crystal structure was detd. by single-crystal X-ray diffraction. In4Ti1.5Mo0.5Mo14O26 crystallizes in the orthorhombic space group Pbca with unit-cell parameters a=9.4432(14) Å, b=11.4828(12) Å, c=20.299(4) Å and Z=4. Full-matrix least-squares refinement on F2 using 3807 independent reflections for 219 refinable parameters resulted in R1=0.0259 and wR2=0.0591. The crystal structure contains in addn. to Mo14 clusters the first examples of mono- and bi-capped trioctahedral Mo14 i.e. Mo15 and Mo16 clusters. The oxygen framework derives from a stacking along the a direction of close-packed layers with sequence (...ABAC...). The Mo-Mo distances range between 2.6938(5) and 2.8420(6) Å and the Mo-O distances between 1.879(5) and 2.250(3) Å, as usually obsd. in molybdenum oxide clusters. The indium atoms form In6+4 bent chains with In-In distances of 2.6682(5) and 2.6622(8) Å and the Ti atoms are in highly distorted octahedral sites of oxygen atoms with Ti-O distances ranging between 1.865(4) and 2.161(4) Å. Magnetic susceptibility measurements confirm the presence of Ti4+ cations and the absence of localized moments on the Mo network. Elec. resistivity measurements on a single crystal of In4Ti1.5Mo0.5Mo14O26 show a semimetallic behavior.

Mots clés: Reduced molybdenum oxide; Molybdenum clusters; Disordered crystal structure; Magnetic susceptibility; Resistivity measurement

Domaines: Chimie; Matériaux

Philippe Gall, Thierry Guizouarn, Patrick Gougeon. 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.. Journal of Solid State Chemistry, 2015, 227, pp.98--103. ⟨10.1016/j.jssc.2015.03.030⟩. ⟨hal-01153431⟩