Possible Piezoelectric Materials CsMZr_0.5(MoO₄)₃ (M = Al, Sc, V, Cr, Fe, Ga, In) and CsCrTi_0.5(MoO₄)₃: Structure and Physical Properties

Abstract

A series of isostructural trigonal molybdates CsMZr 0.5 (MoO 4 ) 3 with M = Al, Ga, In, Sc, Cr, V, Fe, and CsCrTi 0.5 (MoO 4 ) 3 was synthesized by solid state reactions and characterized by synchrotron powder diffraction, differential scanning calorimetry, thermal conductivity measurements, and magnetization measurements for compounds with a magnetic 3d transition metal cation. The NASICON-type structure of these compounds represents a three-dimensional framework of corner-sharing trigonal MoO 4 -pyramids and MO 6 -octahedra, in which M and Zr (Ti) ions are randomly distributed. The Cs ions occupy large channels along the c-axis. A combination of phenomena like a drastic increase of thermal conductivity, endothermic signals in the DSC curve and anomalies in the thermal expansion coefficients, observed for the compounds with M = Cr, V, Fe, and CsCrTi 0.5 (MoO 4 ) 3 above 700 K, allows one to propose a structural phase transition. The crystal structure of the hightemperature phase is very close to the low-temperature one. A significant hysteresis in high-temperature electronic and thermal conductivity was observed. A possible transition from the piezoelectric to the paraelectric state is discussed.

Electronic structure of β-RbSm(MoO4)2and chemical bonding in molybdates

“…These specific structural features generate a diverse crystal chemistry of complex molybdates and provide high feasibility for the incorporation of different doping metals, including rare-earth elements. [7][8][9][10][11][12][13] Several complex molybdates have been grown in the single crystal form, and basic physical parameters have been measured in detail. [14][15][16][17][18][19][20] However, only for a limited number of simple and complex Mo 6+ -oxides have the electronic structures been studied by theoretical or experimental methods.…”

New molybdates in the Rb2MoO4–MI2MoO4–Zr(MoO4)2 (MI – Na, K) systems as promising ion-conducting materials

“…Исследования фазовых равновесий в многокомпонентных системах позволяют получить данные по формированию новых фаз и играют большую роль в поиске новых соединений. Важное место среди большого класса неорганических соединений представляют молибдаты, перспективные как лазерные, сцинтилляционные, сегнетоактивные, нелинейно-оптические и люминесцентные материалы [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Комплексные молибдаты, содержащие щелочные металлы, обладают ионопроводящими свойствами [1, 3 -7].…”

New triple molybdate Rb2AgIn(MoO4)3: synthesis, framework crystal structure and ion-transport behaviour

“…In recent years, numerous triple molybdates (i.e. containing three sorts of cations and MoO 4 anions) have been synthesized (Kozhevnikova & Mokhosoev, 1992;Khaikina et al, 2011Khaikina et al, , 2015Sarapulova et al, 2014), which may be of great interest due to their potential applications as luminescent and laser-host materials, ferroics, ionic conductors etc. For example, the isostructural triple molybdates Li 3 Ba 2 R 3 (MoO 4 ) 8 (R = Ln or Y) (Solodovnikov et al, 2007;Khaikina et al, 2011;Klevtsova et al, 1992) and LiMR 2 (MoO 4 ) 4 (M = K, Rb or Tl; R = Ln, Y or Bi) (Solodovnikov et al, 2007;Khaikina et al, 2011;Morozov et al, 2001) are stuffed derivatives of the BaNd 2 (MoO 4 ) 4 type (Kiseleva et al, 1979) and promising materials for effective phosphors, white LEDs and active lasers (Morozov et al, 2001;Song et al, 2009;Xie et al, 2011).…”