Similarities and differences of crystal structure of internal complex compounds of copper and nickel

Abstract

1. It can be predicted theoretically that if crystals of corresponding copper and nickel internal complexes are not isostructural then in at least one of them the metal atoms are not at the centers of symmetry (the complex is nonplanar). This is confirmed by experimental data. 2. The existing (somewhat limited) experimental data show that in the M−4O and M−4S groups the corresponding copper and nickel compounds are not isostructural, but in the first of these groups copper atoms and in the second nickel atoms are at the centers of symmetry. 3. Diamagnetic nickel compounds of the M−N,20 group (trans) usually form crystals isostructural with the crystals of the corresponding copper compounds, and in most cases the metal atoms are at the centers of symmetry. However, several exceptions are known. In known cases in the M→N,20(cis) group corresponding copper and nickel compounds are not isostructural. 4. Because of the paucity of structure data on crystals of compounds in the M−4N group, no definite conclusions can be drawn. Cases of similarity as well as sharp difference between the structures of corresponding internal copper and nickel complexes are known.