University Chemistry ›› 2019, Vol. 34 ›› Issue (7): 95-99.doi: 10.3866/PKU.DXHX201901034

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Discussion on Iron Oxidation State in "Brown-Ring" Reaction Product

Yuxuan QIAN,Tao CHEN,Xiaofeng CHEN,Jianchun BAO,Min FANG*(),Jiangyan DU,Yong WU*()   

  • Received:2019-01-24 Published:2019-04-11
  • Contact: Min FANG,Yong WU;
  • Supported by:


The oxidation state of iron in the "brown-ring" reaction product[Fe(NO)(H2O)5]2+ and the bond between Fe and NO in this cation are discussed in detail. After presenting different views from the literature based on experimental evidences and theoretical calculations, the oxidation state of iron resonates between +2 and +3 inclining to +2. The Fe-N-O bond angle is 180°. In addition, we proposed an explanation for the slightly shortening of the bond length of NO after coordination to the iron ion.

Key words: Brown-ring reaction, Oxidation state of Iron, Bond angle, Bond length