Synthesize novel highly-nuclear polytungstoarsenate cluster by careful control of pH value

Abstract The self-assembly of [As 2 W 19 O 67 (H 2 O)] 14− precursors in acidic aqueous solution with different pH value led to the isolation of a new highly-nuclear polytungstoarsenate aggregates, [{(W 4 O 9 )(H 2 O) 2 }{As 2 W 19 O 67 (H 2 O)} 2 ] 22− 1 . It can be characterized as two [As 2 W 19 O 67 (H 2 O)] 14− units hinged together by a {(W 4 O 9 )(H 2 O) 2 } fragment. Polyoxoanion 1 is the second largest polytungstoarsenate cluster composed of new {As 2 W 21 } building blocks. Crystal data for 1 : triclinic, space group C 2, a  = 26.274(5) A, b  = 24.321(5) A, c  = 18.764(4) A, β  = 128.58(3)°, V  = 9373(3) A 3 , Z  = 2.