Syntheses of Two Vanadium Oxide–Fluoride Materials That Differ in Phase Matchability

Abstract

The syntheses of two noncentrosymmetric (NCS) vanadium oxide–fluoride compounds that originate from the same synthetic reagent concentrations are presented. Hydrothermal and low-temperature syntheses allow the isolation of metastable products that may form new phases (or decompose) upon heating and allow creation of chemically similar but structurally different materials. NCS materials synthesis has been a long-standing goal in inorganic chemistry: in this article, we compare two chemically similar NCS inorganic materials, NaVOF4(H2O) (I) and NaVO2–xF2+x (II; x = 1/3). These materials originate from the same, identical reagent mixtures but are synthesized at different temperatures: 100 °C and 150 °C, respectively. Compound I crystallizes in Pna21: a = 9.9595(4) Å, b = 9.4423(3) Å, and c = 4.8186(2) Å. Compound II crystallizes in P21: a = 6.3742(3) Å, b = 3.5963(2) Å, c = 14.3641(7) Å, and β = 110.787(3)°. Both materials display second-harmonic-generation activity; however, compound I is type 1 non-phase-matchable, whereas compound II is type 1 phase-matchable.

Design and Synthesis of a Series of Novel Mixed Borate and Carbonate Halides

“…Therefore, we attempted to introduce the CO 3 group into borate systems to explore novel non‐centrosymmetric crystals. We also tried to introduce halogens into the system to expand the structural diversity . Based on above synthetic strategy, a series of novel mixed borate and carbonate halides are discovered, which include Rb 9 [B 4 O 5 (OH) 4 ] 3 (CO 3 )I ⋅ 7 H 2 O (RbBCOI), Rb 9 [B 4 O 5 (OH) 4 ] 3 (CO 3 )Br ⋅ 7 H 2 O (RbBCOBr), Rb 9 [B 4 O 5 (OH) 4 ] 3 (CO 3 )Cl ⋅ 7 H 2 O (RbBCOCl), K 9 [B 4 O 5 (OH) 4 ] 3 (CO 3 )I ⋅ 7 H 2 O (KBCOI), and K 9 [B 4 O 5 (OH) 4 ] 3 (CO 3 )OH ⋅ 7 H 2 O (KBCOH), crystallizing in the non‐centrosymmetric space group P 2 c .…”

Nature of phase transitions in ammonium oxofluorovanadates, a vibrational spectroscopy study of (NH4)3VO2F4 and (NH4)3VOF5

“…The search for novel transition metal oxide fluorides is of interest since the differing bonding natures of the M-O bond and the M-F bond give rise to dramatic variations in and, potentially, fine control of the physical properties of the resulting materials. Recently, various vanadium oxide-fluoride (VOF) compounds have been proposed for use as battery (mainly, silver vanadium oxide fluorides) [1][2][3][4][5][6], nonlinear optical (NLO) materials displaying second-harmonic-generation (SHG) activity [7][8][9], or VOFs with magnetic responses [10][11][12][13][14][15][16].…”

Interplay between Oxo and Fluoro in Vanadium Oxyfluorides for Centrosymmetric and Non-Centrosymmetric Structure Formation

“…Synthesis of the heteroanionic solid is also challenging because of the different energetics of the metal-heteroanion bond, let alone the problem of mixed occupancy/disorder [ 13 , 14 ]. One of the important systems of heteroanionic compounds that has been explored to some extent relates to vanadium oxy-fluorides, which often contain a V = O terminal bond, especially at +4/+5 oxidation state, that can be exchanged with a fluoride under appropriate conditions [ 15 , 16 , 17 , 18 , 19 ]. The Poeppelmeir group has investigated this system in presence of sodium and other ions, which has resulted in materials that show interesting electrochemistry and second-harmonic-generation (SHG) activities, respectively [ 17 , 18 , 19 ].…”

“…One of the important systems of heteroanionic compounds that has been explored to some extent relates to vanadium oxy-fluorides, which often contain a V = O terminal bond, especially at +4/+5 oxidation state, that can be exchanged with a fluoride under appropriate conditions [ 15 , 16 , 17 , 18 , 19 ]. The Poeppelmeir group has investigated this system in presence of sodium and other ions, which has resulted in materials that show interesting electrochemistry and second-harmonic-generation (SHG) activities, respectively [ 17 , 18 , 19 ]. Synthesis of the latter producing the non-centrosymmetric (NCS) crystals also exemplifies how the same reactant composition can lead to two different NCS crystals with varying amounts of fluorine as a function of time and temperature [ 19 ].…”