Crystal structure of tetrabutylammonium tetraiodotriargentate, Bu4N[Ag3l4]

Abstract

The crystal structure of tetrabutylammonium tetraiodotriargentate has been elucidated by single-crystal X-ray analysis. The crystals are monoclinic, with Z= 4 in a unit cell of dimensions a= 9·45, b= 15·77, c= 18·88 Å, β= 101° 08′, space group P2₁/c. The [Bu₄N] units are discrete, but the [Ag₃I₄] moiety is polymeric and exists in the crystal as an extended chain in the a direction. The chain is built up from pairs of Agl₄ tetrahedra sharing one edge, and these units are joined to other similar units by sharing the four free corners. Every tetrahedron contains one Ag atom, but of the octahedral sites defined between adjacent pairs of double tetrahedra, alternate ones contain two Ag atoms 3·13 Å apart. The distance between Ag atoms in the double tetrahedra is 3·06 Å, and the Ag–I distances range from 2·73 to 3·12 Å. The co-ordination states of the Ag atoms and the mode of bonding are discussed.