A number of complexes [Ru(en),]S?, where X = I-, Br-, P~C I A~-, CIOA-, and PFe-, have been prepared and their infrared spectra measured in the solid state between 4 000-600 cm-l. The effect of the various anions on the spectra and assignments for the observed fundamental vibrations are discussed.The infrared spectra of ethylenediamine complexes have recently been reviewed (I). The available infrared data suggest that ethylenediamine coordinates to a metal with the gauche configuration (2). This has been substantiated by X-ray structural data for a number of ethylenediamine colnplexes (3, 4, 5). In this paper we report the preparation of a series of ruthenium(I1) complexes, [ R~( e n )~l X ? , where en = ethylenediamine and X = I-, Br-, PtClt-, C1O4-, and P F c . The infrared data for these coinplexes are given in Table I. Data for the N-deuterated con~plexes are found in Tables I1 and 111.