STRUCTURE OF INCOMMENSURATELY MODULATED Rb[Cr(eida)2]

Gernot Zahn1, Martin Boddin2, Roland Meier2

1 Institut für Kristallographie und Festkörperphysik, Technische Universität Dresden, D 01062 Dresden, Germany, email: zahn@physik.tu-dresden.de
2 Institut für Anorganische Chemie, Universität Leipzig, Talstr. 33, D 04103 Leipzig, Germany

Keywords: crystal structure, coordination compound, incommensurate modulation

The X-ray single-crystal structure analysis of the rubidium salt of trans-bis-N-ethyliminodiacetato chromium(III) (1) has shown that 1 crystallizes incommensurately modulated with the superspace group C 2/c (00) (a = 16.994(2), b = 7.4364(9), c = 13.447(2) A, b = 111.534(9)°, q = 0.362(1)b*). The complex ion in 1 is centrosymmetric and the CrIII center has CN 6.

In the related structure of Rb[Cr(mida)2] (2, mida = N-methyliminodiacetate), the complex ions differ from those in the title compound by a closer packing and a lower flexibility of the ligand. As a consequence, 2 crystallizes in the conventional space group C 2/c without modulation.

Fig. 1: Coordination polyhedron

Fig. 2: Cell projection along [010]