Square planar silver(I) complexes: A rare but increasingly observed stereochemistry for silver(I)

The square planar Ag(I) stereochemistry is generally acknowledged as rare, with only ∼2% of all reported silver complexes possessing this stereochemistry. Many researchers reporting such complexes often mistakenly believe that their example is one of only a handful of previously reported examples. This is despite the fact that there are currently around 65 well characterised complexes containing square planar Ag(I) ions, about half of which are coordination polymers. In this review, we critically examine each example and draw attention to trends that arise in their formation. The scope is limited to ‘traditional’ coordination complexes. Inorganic complexes containing extended mineral like structures, and complexes containing silver-π or silver-arene motifs are not considered in this review.