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

Kulichenko, V., Nedilko, S., Dziazko, O., Chornovol, V. (2015). A STUDY OF NONSTOICHIOMETRIC OXIDES IN THE Ln-Ni-O (Ln=La, Pr, Nd) SYSTEM. French-Ukrainian Journal of Chemistry, 3(2), 89–92. https://doi.org/10.17721/fujcV3I2P89-92

The non-stoichiometric compositions Ln2-xNiO4-3x/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 La2NiO4.17 – La1.6NiO3.63 are monophase and crystallize in tetragonal symmetry K2NiF4, space group I4/mmm.  Nd2-xNiO4-y  and Pr2-xNiO4-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.