Aust. J. Chem., 1984,37, 1111-5 Crystal Structure of Diaqua(1,lO-phenanthroline)copper(~~) Sulfate Peter C. Healy; Jennifer M. PatrickB and Allan H. whiteB A School of Science, Griffith University, Nathan, Qld. 41 11. Department of Physical and Inorganic Chemistry, University of Western Australia, Nedlands, W.A. 6009. Abstract The crystal structure of the title compound, [C~(OH~)~(phen)] (SO,) (phen = 1,lO-phenanthroline), has been determined by single-crystal X-ray diffraction methods at room temperature, being refined by full matrix least-squares methods to a residual of 0.033 for 1445 'observed' reflections. Crystals are monoclinic, CZ/c, a 14.883(8), b 13.843(9), c 7.019(4) A, B 108.60(4)", Z 4. As in a number of other copper(^^) and nickel@) derivatives with (CuL4)(S04) stoichiometry, the pseudo-square planar copper environments [Cu-N,O: 2.009(2), 1.970(2) A in the present case] are bridged through the two axial coordination positions by sulfate groups: 0.S02.0[Cu(OH2)2(phen)]0.S02.0, etc. to give a linear polymeric array [Cu-0(S04), 2.468(3) A]; a crystallographic twofold axis passes through the copper atom. Introduction Elsewhere in this issue1 we have described the single-crystal X-ray structure determinations of [Ni(OH2),LI2+ species, L = ethylenediamine, 2,2'-bipyridyl, comparing the geometries of the two cations with the parent [Ni(OH2),I2+ and [NiL,I2+ species. Although similar parent [Cu(OH2),12+ and [CuL,I2' species are found for copper(^^), species of the type [Cu(OH2),LI2+ have not been described structurally, nor do they appear to occur stoichiometrically. However, species of the type [Cu(OH,),L] (SO,) are known, together with a nickel(11) counterpart. For [Cu(OH,),(en)] (SO,), a structure determination of diffractometer quality is available,, showing the fifth and sixth (axial) coordination sites of the copper atom to be filled by sulfate oxygen atoms; structure determinations of the isomorphous pair [Ni,Cu(OH,),(bpy)] (SO,) by film methods are a ~ a i l a b l e , ~ displaying a structure similar to that of [Cu(OH,),(en)] (SO,). Rather than repeat the bipyridyl structure in order to obtain the desired precision for comparative purposes, we have made similarly the 1,lO-phenanthroline analogue, [Cu(OH,),(phen)] (SO,), and report its structure determination hereunder. An atom designation has been adopted which gives a connected set within the one polymer string. Healy, P. C., Patrick, J. M., and White, A. H., Aust. J. Chem., 1984, 37, 921. Healy, P. C., Kennard, C. H. L., Smith, G., and White, A. H., Cryst. Struct. Commun., 1978, 7, 565. Tedenac, J. C., and Philippot, E., J. Inorg. Nucl. Chem., 1975, 37, 846; Acta Crystallogr., Sect. B, 1974, 30, 2286.