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Title: Intercalation in montmorillonite of molybdenum cations containing the Mo/sub 6/Cl/sub 8/ cluster core

Journal Article · · J. Solid State Chem.; (United States)

Molybdenum cations containing the Mo/sub 6/Cl/sub 8/ cluster core have been intercalated in montmorillonite. cluster ions of the type (Mo/sub 6/Cl/sub 8/(H/sub 2/O)/sub 6-n/(OH)/sub n/)/sup (4-n)+/ were formed by argentometric titration of (Mo/sub 6/Cl/sub 8/)Cl/sub 4/ x 2H/sub 2/O to remove the four terminally bonded chlorines. At pH = 1.5 the clusters occupy the gallery region between the silicate layers of montmorillonite by displacement of Na/sup +/. The cluster intercalates mainly as monopositive cations (n = 3), along with some dipositive cations (n = 2). The maximum cluster loading (80 mmoles/100 g) exceeds the value expected on the basis of ion exchange alone (60 mmoles/100 g). The gallery height of 7.3 A for the new intercalate is compatible with the C/sub 4/ axis of the Mo/sub 6/Cl/sub 8/ core being oriented perpendicular to the silicate layers. Thermolysis of the intercalated clusters at 240/sup 0/C results in the oxidation of the intercalated clusters to molybdenum oxide. Cluster decomposition is accompanied by the collapse of some galleries, while others remain propped open by 3.9 A. The latter value corresponds to two layers of oxygen in the galleries. Thus the oxide is nonuniformly distributed on both the internal and external surfaces of the clay. Complete gallery collapse is observed at 300/sup 0/C.

Research Organization:
Michigan State Univ., East Lansing
OSTI ID:
6954830
Journal Information:
J. Solid State Chem.; (United States), Vol. 64:3
Country of Publication:
United States
Language:
English