Copper arsines, structure

Silver iodide derivatives of trialkyl-phosphines and -arsines were prepared in 1937 for comparison with their copper(I) iodide analogues.201 The preparations involved shaking the ligands with silver iodide dissolved in concentrated aqueous KI. The products were found to be tetramers and of similar structure to the Cu1 complexes. The Pr As silver complex was isomorphous with [Cul-AsEt3]4. Molecular weight determinations in a range of organic solvents showed that partial dissociation occurred in solution. 

This coordinated structure, which was entirely novel in 1936, is not limited to copper(I) iodide derivatives. Silver(I) iodide forms similar tetrameric compounds with tertiary phosphines and arsines, and since tetrakis(monoiodo-tri-n-propylarsinesilver), [ (C3H 7) 3As,Agl]4, is strictly isomorphous with tetrakis (monoiodo-triethylarsinecopper), the two series have identical structures Hi). 

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