Crystal structures of acid ethylenediaminetetraacetates [Cd(H(2)Edta)(H2O)]center dot 2H(2)O and [Mn(H2O)(4)][Mn(HEdta)(H2O)](2)center dot 4H(2)O

The crystal structures of [Cd(H(2)Edta)(H2O)] . 2H(2)O (I) and [Mn(H2O)(4)] [Mn(HEdta)(H2O)](2) . 4H(2)O (II) are studied by X-ray diffraction [R-1 = 0.0209 (0.0272), wR(2) = 0.0571 (0.0730) for 2551 (4025) reflections with I > 2 sigma (I) in I(II), respectively]. Structure I contains mononuclear [C d(H(2)Edta)(H2O)] complexes with the C-2 symmetry, and structure II contain s centrosymmetric trinuclear [Mn(H2O)(4)] [Mn(HEdta)(H2O)](2) complexes. In I and II, the protonated ligands are hexadentate (2N + 4O), and the water molecule increases the coordination number of the metal atom to seven. The acid protons participate in short intermolecular hydrogen bonds, which are symmetric in II and asymmetric in I. (C) 2001 MAIK "Nauka/Intrerperiodica " .