A₃V₅O₁₄ (A = K⁺, Rb⁺, or Tl⁺), New Polar Oxides with a Tetragonal Tungsten Bronze Related Structural Topology: Synthesis, Structure, and Functional Properties

Abstract

Three polar noncentrosymmetric (NCS) oxide materials, A(3)V(5)O(14) (A = K(+), Rb(+), or Tl(+)), have been synthesized by hydrothermal and conventional solid state techniques. Their crystal structures and functional properties (second-harmonic generation, piezoelectricity, and polarization) have been determined. The iso-structural materials exhibit a layered structural topology that consists of corner-sharing VO(4) tetrahedra and VO(5) square pyramids. The layers stack parallel to the c-axis direction and are separated by the K(+), Rb(+), or Tl(+) cations. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation indicate the materials exhibit moderate SHG efficiencies of approximately 100 x alpha-SiO(2). Additional SHG measurements, that is, particle size versus SHG efficiency, indicate the materials are type-I phase-matchable. Converse piezoelectric measurements for K(3)V(5)O(14), Rb(3)V(5)O(14), and Tl(3)V(5)O(14) revealed d(33) values of 28, 22, and 26 pm/V, respectively. Pyroelectric measurements, that is, temperature-dependent polarization measurements, resulted in pyroelectric coefficients of -2.2, -2.9, and -2.8 microC/m(2) x K at 65 degrees C, for K(3)V(5)O(14), Rb(3)V(5)O(14), and Tl(3)V(5)O(14) respectively. Frequency-dependent polarization measurements confirmed that all of the materials are nonferroelectric, consistent with our first principle density functional theory (DFT) electronic structure calculations. Infrared, UV-vis, thermogravimetric, and differential scanning calorimetry measurements were also performed. Crystal data: K(3)V(5)O(14), trigonal, space group P31m (No. 157), a = 8.6970(16) A, c = 4.9434(19) A, V = 323.81(15), and Z = 1; Rb(3)V(5)O(14), trigonal, space group P31m (No. 157), a = 8.7092(5) A, c = 5.2772(7) A, V = 346.65(5), and Z = 1; Tl(3)V(5)O(14), trigonal, space group P31m (No. 157), a = 8.7397(8) A, c = 5.0846(10) A, V = 336.34(8), and Z = 1.

Bond-length distributions for ions bonded to oxygen: results for the transition metals and quantification of the factors underlying bond-length variation in inorganic solids

“…5 O 14 (ICSD 248227;Yeon et al, 2010), a priori (observed bond valences are 1.430 (1.601) and 3 Â 1.190 (1.169) v.u., with Á topol = 0.090 and Á cryst = 0.059 v.u for V1, and 1.220 (1.647), 2 Â 0.980 (0.938) and 2 Â 0.910 (0.738) v.u., with Á topol = 0.088 and Á cryst = 0.171 v.u for V2. For V1, nonlocal bond-topological asymmetry is mainly responsible for variation away from a regular tetrahedron with four bonds of 1.25 v.u.…”

“…5 O 14 is observed with a series of marked functional properties, i.e. second-harmonic generation, piezoelectricity and polarization (Yeon et al, 2010).…”

[R-C7H16N2][V2Te2O10] and [S-C7H16N2][V2Te2O10]; new polar templated vanadium tellurite enantiomers

“…The strategies that are most commonly employed for the creation of new polar materials involve the use of asymmetric building units [4][5][6][7][8][9][10]. Specific approaches include the use of d 0 early transition metals (Ti 4 þ , V 5 þ , Mo 6 þ , etc.)…”

Growth, Properties, and Theoretical Analysis of M2LiVO4 (M = Rb, Cs) Crystals: Two Potential Mid-Infrared Nonlinear Optical Materials

“…In recent research, many studies pay special attention to halides, iodates, molybdates, and vanadates since they normally exhibit large E g and diverse structural motifs so that it is possible to find materials with a subtle balance between large NLO efficiency and high LDT. A series of potential Mid-IR NLO crystals have been achieved, such as Pb 17 O 8 Cl 18 19 , α -AgI 3 O 8 and β -AgI 3 O 8 20 , RbIO 3 21 , Na 2 Te 3 Mo 3 O 16 22 , BaTeMo 2 O 9 23 , LiNa 5 Mo 9 O 30 24 , K 3 V 5 O 14 25, 26 and YCa 9 (VO 4 ) 7 27 . After a lot of screening and system performance evaluation, we think that Rb 2 LiVO 4 (RLVO) and Cs 2 LiVO 4 (CLVO) are good Mid-IR NLO materials.…”