The structure of [NEt4]6[H4Na2(PH)6Mo12O54]·4H2O (1) has been determined by the single-crystal X-ray method. The crystals are monoclinic, space group of C2/c, with cell parameters a = 23.790(3), b = 16.319(2), c = 28.788(3) A, β = 114.365(7)°, and Z = 4. The structure model was refined by full-matrix least squares to R = 0.0624 and Rw = 0.0661 for 6798 independent reflections with Fo > 3σ(F) and in 2θ < 50°. The existence of a meso-type heteropolyion [H4Na2(PH)6Mo12O54]6− (2) in the title crystals has been confirmed. It is composed of a pair of enantiomeric moieties of [H2Na(PH)3Mo6O27]3− (3 and 3i, respectively) which are linked by sharing Na+ ions; here, the superscript i denotes the symmetrical operation code of (1/2−x, 1/2−y, −z). The six MoO6-octahedra contained in the respective moieties are arranged to form Plus- and Minus-helices.

The Structure of a Meso-Type Heteropolyion of Tetrahydrogen Disodium Dodecamolybdohexaphosphonate(III) (6−) Contained in [NEt4]6[H4Na2(PH)6Mo12O54]·4H2O

The title compound was isolated from a 0.15 M (= mol/dm3) Mo(VI)/0.3 M H3PO3/0.1 M HCl/60% (v/v) CH3COCH3 system. The existence of a new type of heteropoly complex with a composition of Mo/P = 6/5 was elucidated. The formation conditions and the IR spectroscopic characteristics were compared with those of well-established pentamolybdodiphosphonate.

Synthesis of Colorless (6/5)-Molybdophosphonate, Na2H5[(C2H5)4N]3(HP)5Mo6O33

The structure of the first heteropolyanion, [P4W8O40]12–, with an X:M ratio of 1:2, has been determined from single crystal X-ray studies of the sodium salt; the idealized anion has 2m symmetry and consists of a shell of WO6 octahedra and PO4 tetrahedra made up of four PW2O13 groups linked by corner sharing and a sodium atom is situated in the centre of the polyanion.

Alex J. Jozsa

Papers

X-Ray crystal structure of a new heteropolyanion, [P4W8O40]12–, with an X:M ratio of 1:2