ISSN 1023-1935, Russian Journal of Electrochemistry, 2015, Vol. 51, No. 7, pp. 615–618. © Pleiades Publishing, Ltd., 2015. Original Russian Text © Yu.G. Mateyshina, A.A. Iskakova, A.S. Ulihin, N.F. Uvarov, 2015, published in Elektrokhimiya, 2015, Vol. 51, No. 7, pp. 699–702. 615 INTRODUCTION The mechanism of formation and migration of charge carriers in orientation–disordered phases of ionic salts is as yet not elucidated. Orientation–disor- dered phases are characterized by presence of free vol- ume distributed nonuniformly over the disordered ion sublattice, so the structure contains loose crystal lat- tice regions exhibiting decreased values of migration energy, over which accelerate ion transport can occur [1, 2]. In its turn, the very mechanism of ion transport is cooperative and includes simultaneous act of ion jump and reorientation movements of the counterions surrounding it. The latter mechanism known in the lit- erature as “the paddle wheel mechanism” was sug- gested for description of fast ion transport in the high– temperature lithium sulfate phase [3, 4]. As shown earlier, an increase in free volume in orientation–dis- ordered phases with tetrahedral anions, e.g., in alkali perchlorates [5, 6] and rubidium and cesium phos- phates [7, 8], results in an increase in conductivity. Here, conductivity is carried out by large rubidium or cesium cations. Such behavior is also qualitatively characteristic for nitrates, where the highest ion con- ductivity is typical for rubidium nitrate [9, 10]. The results of computer simulation showed that migration energy in rubidium nitrate was low and ion conductiv- ity was limited by the process of formation of Schottky defects [1, 11]. We have showed recently that the dependence of conductivity on ionic radius in a series of alkali nitrites passes through a minimum with rubidium nitrite and increases drastically at a transi- tion from RbNO 2 to CsNO 2 [12, 13]. Taking into account that the high–temperature cesium nitrite phase is orientation–disordered, one can expect that the mechanism of ion transport in this compound is cooperative, which is what causes relatively high ion conductivity of this compound. There are data in the literature on structural and thermodynamic properties of cesium nitrite, but transport properties of this salt have never been studied earlier. In this work, studies of conductivity of nominally pure and doped sampled of cesium nitrite are carried out to elucidate the nature of charge carriers and mechanism of conductivity. EXPERIMENTAL Cesium nitrite was synthesized in the exchange reaction between Cs 2 SO 4 and Ba(NO 2 ) 2 with the fur- ther washing and recrystallization of the deposit. Syn- thesis of the sample doped by barium nitrite, 0.99CsNO 2 ⋅ 0.01Ba(NO 2 ) 2 , was carried out by the thorough mixing of reagents and mixture heating at the temperature of 405°С for 30 min. This procedure has been carried out several times to achieve a more uniform distribution of barium nitrate in CsNO 2 . The crystalline structure of the obtained CsNO 2 was ana- lyzed using the method of X-ray diffraction with the help of a D8 Advance diffractometer (Germany) in CuKα radiation. Thermal analysis of samples was car- ried out at a 550 SSI differential scanning calorimeter (DSC) (USA) (the temperature variation rate was 10 degrees/min). In conductivity studies, samples are heated at the temperatures of 405°С for 30 min, cooled, then tablets with embedded silver and/or car- bon electrodes were formed of them under the pres- sure of 400 MPa. The values of density of the obtained tablets were 95–98% of the theoretical density. Con- Transport Properties of Cesium Nitrite 1 Yu. G. Mateyshina a, b, z , A. A. Iskakova a , A. S. Ulihin a , and N. F. Uvarov a, b a Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences, ul. Kuteladze 18, Novosibirsk, 630128 Russia b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia Received August 19, 2014 Abstract—Data on studies of the phase composition, thermal and transport properties of cesium nitrite are presented. Transport properties of the salt, including a sample doped by barium cations, are studied in detail. Values of enthalpies of defect formation and migration are estimated. The Hebb–Wagner method was used to evaluate the contribution of electron–hole conductivity. It is shown that conductivity is ionic and charge car- riers are cesium ions migrating over cation vacancies. Keywords: cesium nitrites, ion conductivity, orientation–disordered phases DOI: 10.1134/S1023193515060154 1 Based on the paper presented at the XII Meeting “Fundamental Problems of Solid State Ionics,” Chernogolovka (Russia), July 3–5, 2014. z Corresponding author: YuliaM@solid.nsc.ru (Yu.G. Mateyshina).