Oxygen ion and electron conductivity in fluorite-like molybdates Nd 5 Mo 3 O 16 and Pr 5 Mo 3 O 16

Phase Relations and Physical Properties of Layered Pb‐Containing Nd2MoO6 Compounds

“…The samples with high Pb content underwent a reversible first-order phase transition near 820°C. [6][7][8][9][10][11] Compounds with such a structure can be synthesized for Ln = La, Pr, Nd, Sm, and Gd under reducing conditions, [9] and only for Pr and Nd in air. In the region of the phase transition, the permittivity of the Pb-containing samples show a strong lambda-type anomaly and electrical conductivity increases…”

“…XRD analysis revealed two tetragonal phases, the hightemperature centric phase (I4 1 /acd) and the low-temperature acentric phase (I42m). [6,7,10,11] The Ln 5 Mo 3 O 16+δ compounds were found to have mixed oxygen-ion/electronic conductivity, which opens up the possibility of using them in electrochemical devices. Many of these molybdates possess functional properties of practical interest.…”

“…Many of these molybdates possess functional properties of practical interest. [6][7][8][9][10][11] Compounds with such a structure can be synthesized for Ln = La, Pr, Nd, Sm, and Gd under reducing conditions, [9] and only for Pr and Nd in air. [1] In 2000, Lacorre et al reported La 2 Mo 2 O 9 (1:2 compound) to have high oxygen-ion conductivity (0.06 S/cm at 800°C).…”

“…Borchardt and Bierstedt found that the 1:3 compounds, Ln 2 (MoO 4 ) 3 , show ferroelectric properties. [6,7,10,11] The Ln 5 Mo 3 O 16+δ compounds were found to have mixed oxygen-ion/electronic conductivity, which opens up the possibility of using them in electrochemical devices. [2] In air, 1:2 compounds can only be synthesized for Ln = La and Pr.…”

“…[1] In 2000, Lacorre et al reported La 2 Mo 2 O 9 (1:2 compound) to have high oxygen-ion conductivity (0.06 S/cm at 800°C). [9,10] At a slightly higher rare-earth content, 1:1 Ln 2 MoO 6 compounds, so-called oxymolybdates, [12][13][14] exist for all of the rare earths and have different structures depending on the ionic radius of the rare-earth element and the synthesis temperature. [2][3][4][5] A number of Ln 2 O 3 -MoO 3 systems have been found to contain Ln 5 Mo 3 O 16+δ compounds of variable composition with a fluorite-like cubic structure.…”