β-Octamolybdate as a Building Block. Synthesis and Structural Characterization of Rare Earth−Molybdate Adducts

Reaction of [( n -C 4 H 9 ) 4 N] 4 [Mo 8 O 26 ] with nitrate salts of rare earth metals yields two different series of new compounds [Ln(Mo 8 O 26 ) 2 ] 5 - and [{Ln(NO 3 ) 3 } 2 (Mo 8 O 26 )] 4 - (Ln = Y, La, Ce, Pr, Nd, Gd, Yb) as tetra- n -butylammonium salts. X-ray structural analyses of [( n -C 4 H 9 ) 4 N] 5 [La(Mo 8 O 26 ) 2 ]·CH 3 CN [monoclinic, space group P 2 1 / c, a = 25.8332(6) Å, b = 17.5054(7) Å, c = 32.6565(12) Å, β = 91.699(2)°, Z = 4] and [( n -C 4 H 9 ) 4 N] 4 [{La(NO 3 ) 3 } 2 (Mo 8 O 26 )]·2CH 3 CN [monoclinic, space group P 2 1 / n, a = 17.702(2) Å, b = 17.2646(12) Å, c = 18.965(2) Å, β = 102.132(3)°, Z = 2] revealed that these compounds contain the Mo 8 O 26 unit as their building block.