A STUDY OF NONSTOICHIOMETRIC OXIDES IN THE Ln-Ni-O (Ln=La, Pr, Nd) SYSTEM

Vadim Kulichenko; Sergiy Nedilko; Olexander Dziazko; Victoria Chornovol

doi:10.17721/fujcV3I2P89-92

Authors

Vadim Kulichenko Kiev National University of Construction and Architecture http://orcid.org/0000-0001-8427-6167
Sergiy Nedilko Taras Shevchenko National University of Kyiv
Olexander Dziazko Taras Shevchenko National University of Kyiv
Victoria Chornovol Kyiv National University of Building and Architecture http://orcid.org/0000-0002-1156-4229

DOI:

https://doi.org/10.17721/fujcV3I2P89-92

Keywords:

coprecipitation method, non-stoichiometric compositions, nickelates, rare earth oxides, K2NiF4

Abstract

The non-stoichiometric compositions Ln_2-xNiO_4-3x/2+_d (Ln=La, Pr, Nd, 0£x£0,4) were obtained using coprecipitation method from nitrates solutions by K₂CO₃ followed by calcination of the obtained blend at 950°С. According to X-ray phase analysis compositions in the range La₂NiO_4.17 – La_1.6NiO_3.63 are monophase and crystallize in tetragonal symmetry K₂NiF₄, space group I4/mmm. Nd_2-xNiO_4-_y and Pr_2-xNiO_4-_y in the range 0£x£0,2 are monophase and have orthorombic and monoclinic(correspodingly) distorted K₂NiF₄ structure. Samples with 0,2<x£0,4 are polyphase and contain Ln₂NiO₄(Ln=Pr, Nd), NiO and rare earth oxides. Electrical conductivity of obtained samples have semiconducting behavior and it is strong depended to nonstoichiometric oxygen content.

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