IntroductionWe are investigating the crystal supramolecular motifs adopted by coordinationcomplexes such as [M(phen)n]z+(phen⊕=⊕1,10­phenanthroline),1,2and the supramolecularity of the relativelystrong intermolecular forces between iodinous units (coordinated anduncoordinated iodide, iodine, and polyiodides) in inorganic crystals.Combination of these two systems, as cations [M(phen)n]z+with polyiodide anions, provides a rich if slightly perplexing crystallisationmilieu,and a remarkable collection of crystal structures.3In other papers we describe the trimorphs of [Fe(phen)3]I12,4the dimorphs of [CuI(phen)2]I3,5the crystal structures of [M(phen)3]I7(M⊕=⊕Mn,Fe),6and the crystal structures of [M(phen)3]I8(M⊕=⊕Mn,Fe).7One reason for this richness is the complementarity of the metrical orthogonalityof the cations and anions.4The phen ligandplanes in octahedral [M(phen)3]z+complexes are planar and orthogonal, and sequences of iodine atoms in polyiodideanions also tend to have linear segments connected with approximately orthogonalbond angles and dihedral angles.8–12This allows efficient entwining of cation and anion: polyiodide ions can liealong the faces of the phen ligands, or around their peripheries.3,4Complexes [M(phen)3]z+commonly adopt the parallel fourfold aryl embrace (P4AE), in whichtwo complexes around a centre of inversion use two phen ligands each to formone offset­face­to­face (OFF) and two edge­to­face (EF)local motifs.1,2,4In complexes withanions of relatively low volume these P4AEs are unimpeded, and can associatefurther in chains or layers. However, increased volume of the anions progressivelydisrupts the P4AEs. Here we describe and analyse in detail the crystal structuresof two iodine-rich compounds, [Fe(phen)3]I14and [Fe(phen)3]I18, where this disruptionof cation embraces is pronounced and eventually becomes complete. We interpretthe balance in these crystals of the influences of [Fe(phen)3]2+⋯[Fe(phen)3]2+motifs, polyiodide association patterns,and various [Fe(phen)3]2+⋯polyiodidemotifs, and conclude that details of the polyiodide nets are determined bythe association with [Fe(phen)3]2+,and should not be interpreted otherwise.