Adducts of co-ordination compounds. Part II. Compounds of nitric acid and trans-dihalogenotetrapyridinemetal(III) nitrates

Abstract

The adduct of nitric acid with trans-dibromotetrapyridinerhodium(III) nitrate reported in 1935 contains the hydrogen dinitrate anion, and is now formulated as trans-[Rh py₄Br₂](O₂NO,H,ONO₂). A number of similar adducts of complexes, with formulætrans-[MA₄X₂](O₂NO,H,ONO₂), have been prepared, where M = Co or Rh, A = pyridine or ½(bipyridyl), and X = Cl or Br. The presence of the hydrogen dinitrate anion in all these compounds is demonstrated by analysis, infrared spectroscopy, and by conductivity and pH studies. The adducts are stable compounds, and the anion exists undissociated in some solvents; it probably contains a symmetrical hydrogen bond.