file size: 687 KB, MIME type: image/png) [ edit ] Summary Description Space-filling model of the 1,4,7-trithiacyclononane molecule, cyclic thioether , used as a tridentate ligand . Colour code (click to show)     Black: Carbon, C   White: Hydrogen, H   Blue: Nitrogen, N Date 18 February 2011 ( 2011-02-18