Linear chain compound


Linear chain compounds are materials composed of one-dimensional arrays of metal-metal bonded molecules or ions. Such materials exhibit anisotropic electrical conductivity.

Examples

Most examples are composed of square planar complexes. Thus, upon crystallization, molecules of Rh2 stack with Rh---Rh distances of about 326 pm. Classic examples include Krogmann's salt and Magnus's green salt. Other examples include the partially oxidized derivatives of 2-. The otherwise ordinary complex IrBr3 gives an electrically conductive derivative upon oxidation. Such semiconducting materials are eniched in bromine, i.e. IrBr1+x3-x, where x ~0.05.
In contrast to linear chain compounds, extended metal atom chains are molecules or ions that consist of a finite, often short, linear strings of metal atoms, surrounded by organic ligands.
One group of platinum chains is based on alternating cations and anions of 2+ and 2−. These may be able to be used as vapochromic sensor materials, or materials which change color when exposed to different vapors.
Linear chains of Pd-Pd bonds protected by a “π-electron sheath are known.
Not only do these olefin-stabilized metal chains constitute a significant contribution to the field of organometallic chemistry, both the complex's metal atom structures and the olefin ligands themselves can conduct a current.

Methodology

Some linear chain compounds are produced or fabricated by electrocrystallization. The technique is used to obtain single crystals of low-dimensional electrical conductors.