Composition Space Diagrams for Mixed Transition Metal Oxide Fluorides

Abstract

Composition space diagrams have been used to study phase stability of mixed transition metal oxide fluorides synthesized by hydrothermal reaction of the metal oxides in (HF)(x)().pyridine/H(2)O/pyridine solution (150 degrees C, autogenous pressure). The combination of early (Ti, Zr, Hf, Nb, Ta, Mo, W) and late (Cu, Cd, Zn) transition metals and the effects of varying the mole ratios of the metals, (HF)(x)().pyridine, and water are examined in this study. Single-crystal products containing [Cu(py)(4)](2+), [Cd(py)(4)](2+), or [Zn(py)(4)](2+) cations and [TiF(6)](2)(-), [ZrF(6)](2)(-), [HfF(6)](2)(-), [NbOF(5)](2)(-), [TaOF(5)](2)(-), [MoO(2)F(4)](2)(-), or [WO(2)F(4)](2)(-) anions are recovered. Relative stability of the crystalline products is governed by the negative charge distribution on the anions, as well as the concentrations of each reactant in solution. Two new structures are reported: Cu(NC(5)H(5))(4)TaOF(5) and Cu(NC(5)H(5))(4)TiF(6).3H(2)O. Crystal data: for Cu(NC(5)H(5))(4)TaOF(5), monoclinic, space group C2/c (No. 15), with a = 10.541(3) Å, b = 13.547(6) Å, c = 16.04(1) Å, beta = 97.73(5) degrees, and Z = 4; for Cu(NC(5)H(5))(4)TiF(6).3H(2)O, monoclinic, space group C2/c (No. 15), with a = 12.767(4) Å, b = 12.048(2) Å, c = 17.787(6) Å, beta = 109.9(1) degrees, and Z = 4.

Intramolecular mobility and phase transitions in ammonium oxofluoroniobates (NH4)2NbOF5 and (NH4)3NbOF6, a NMR and DFT study

“…However, these acentric anions are virtually always found to crystallize in centrosymmetric space groups, thus eliminating possible SHG effects [1]. The O/F ordering in a noncentrosymmetric space group has been achieved with the [NbOF 5 ] 2À anion in inorganic-organic hybrid compounds with cluster [2] and chain motifs [3]. In inorganic solid-state environment, the individual Nb-O and Nb-F bonds were recently found [4] to be ordered in noncentrosymmetric KNaNbOF 5 which exhibits the SHG property.…”

Hydrothermal synthesis, crystal structure and property of a barbell-like copper complex with {(μ-F)[(μ-O)2(NbF4)2]} as the handle bar

“…Compared compound 1 with other Nb-Cu metal mixed complexes previously reported [13][14][15][16][17][18], we find that all these compounds are composed of CuL 6 and NbL' 6 fragments with similar bond lengths and bond angles, bridged by O/F atoms. However, the obvious differences of The IR spectrum of compound 1 is studied.…”

“…Conventional synthesis in solution and solid synthesis at high temperature are major techniques to synthesize for preparation of Nb complexes at present [11,12]. Since the 1990s, Poeppelmeier and co-workers have isolated more than ten Nbtransition metal mixed complexes by mild hydrothermal technique and attained their crystal structures [12][13][14][15][16][17][18]. However, it was difficult to synthesize niobium-organic hybrid complexes because the experimental conditions were rigorous.…”

New Layered Oxide-Fluoride Perovskites: KNaNbOF5 and KNaMO2F4 (M = Mo6+, W6+)

“…[33]. Single or multiple pouches were placed in a 125 mL Teflon-lined Parr pressure vessel filled 33% with deionized H 2 O as backfill [34]. The pressure vessel was heated for 24 h at 150 °C and cooled to room temperature over an additional 24 h. The pouches were opened in air, and the products were recovered by vacuum filtration.…”