A new route to prepare the mixed oxo‐ethylidyne‐capped trinuclear tungsten(IV) cluster and the crystal structure of H 2 Na 3 [W 3 O(CCH 3 )‐(O 2 CCH 3 ) 6 (H 2 O) 3 ][H 2 W 12 O 40 ]·13.5H 2 O

The synthesis and the structural characterization of the title compound H 2 Na 3 [W 3 O(CCH 3 )‐(O 2 CCH 3 ) 6 (H 2 O) 3 ][H 2 W 12 O 40 ]·13.5H 2 O are described. It is known that the mixed oxo‐ethylidynecapped tritungsten cluster can be obtained by Zn dust reduction of Na 2 WO 4 ·2H 2 O in acetic anhydride. The title compound has been characterized by X‐ray diffraction, UV/VIS and 1 H NMR spectra. The tungsten atoms in the cluster cation and anion are in the oxidation states of W(IV) and W(VI) respectively. The crystal is rhombohedral with the space group R 32, a = 17.058 (3)Å, c = 49.665 (9)Å, γ=120°, V =12516(9)Å 3 , Z =6, final R = 0.037 for 2071 reflections with I ≥3σ ( I ). Both the cluster cation and anion have a C 3 symmetry. The important interatomic distances in angstroms for the cluster cation are: W—W, 2.730(2); W— μ 3 −O, 2.00; W—O (carboxy1), 2.12; W—O t 2.18 (2).