Thermal decomposition of potassium hexanitronickelate(II) hydrate


Subasi E., Almond M.

THERMOCHIMICA ACTA, vol.429, no.2, pp.227-231, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 429 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1016/j.tca.2005.02.018
  • Journal Name: THERMOCHIMICA ACTA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.227-231
  • Keywords: thermal analysis, nickel(II), nitro, potassium salt, X-ray diffraction, IR data, METAL NITRITE COMPLEXES, INFRARED SPECTRA, K4<NI(NO2)6>.H2O, VIBRATION, CRYSTAL, SALTS
  • Dokuz Eylül University Affiliated: Yes

Abstract

The thermal decomposition of the complex K-4[Ni(NO2)6]center dot H2O has been investigated over the temperature range 25-600 degrees C by a combination of infrared spectroscopy, powder X-ray diffraction, FAB-mass spectrometry and elemental analysis. The first stage of reaction is loss of water and isomerisation of one of the coordinated nitro groups to form the complex K-4 [Ni(NO2)(4) (ONO)]center dot NO2. At temperatures around 200 degrees C the remaining nitro groups within the complex isomerise to the chelating nitrite form and this process acts as a precursor to the loss of NO2 gas at temperatures above 270 degrees C. The product, which is stable up to 600 degrees C, is the complex K-4[Ni(ONO)(4)]center dot NO2, where the nickel atom is formally in the +1 oxidation state. (c) 2005 Elsevier B.V. All rights reserved.