Vibrational spectra of metal-nitro complexes. III. The Tetranitro-platinate(II) and -palladate(II) ions

Abstract

The vibrational spectra have been obtained of salts having the general formula M₂[M?(NO₂)₄] where M is Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺ and M? is Pt^II or Pd^II. In solution the spectra were best assigned to a D_4h point group (tetranormal arrangement of NO₂ groups). In the solid state factor group splitting was evident but the number of bands observed was fewer than predicted. Where the structure was not known approximate assignment was made by analogy with known structures. The spectra indicate that π- bonding between metal and nitrogen is more pronounced for the complexes of platinum(II).