Composition Space Diagrams for Mixed Transition Metal Oxide Fluorides

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/H2O/pyridine solution (150 °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 [TiF6]2-, [ZrF6]2-,
[HfF6]2-, [NbOF5]2-, [TaOF5]2-, [MoO2F4]2-, or [WO2F4]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(NC5H5)4TaOF5 and Cu(NC5H5)4TiF6·3H2O.
Crystal data:  for Cu(NC5H5)4TaOF5, monoclinic, space group C2/c (No. 15), with a = 10.541(3) Å, b = 13.547(6)
Å, c = 16.04(1) Å, β = 97.73(5)°, and Z = 4; for Cu(NC5H5)4TiF6·3H2O, monoclinic, space group C2/c (No.
15), with a = 12.767(4) Å, b = 12.048(2) Å, c = 17.787(6) Å, β = 109.9(1)°, and Z = 4.

本研究采用组成空间图（composition space diagrams），针对以金属氧化物为原料，在(HF)ₓ·吡啶/水/吡啶溶液（150℃、自生压力）中水热合成的混合过渡金属氧氟化物的相稳定性展开研究。本研究考察了早期过渡金属（early transition metal，包括Ti、Zr、Hf、Nb、Ta、Mo、W）与晚期过渡金属（late transition metal，包括Cu、Cd、Zn）的组合模式，以及金属、(HF)ₓ·吡啶与水的摩尔比变化对合成产物的影响。最终得到了含[Cu(吡啶)₄]²⁺、[Cd(吡啶)₄]²⁺或[Zn(吡啶)₄]²⁺阳离子，以及[TiF₆]²⁻、[ZrF₆]²⁻、[HfF₆]²⁻、[NbOF₅]²⁻、[TaOF₅]²⁻、[MoO₂F₄]²⁻或[WO₂F₄]²⁻阴离子的单晶产物。结晶产物的相对稳定性由阴离子表面的负电荷分布，以及溶液中各反应物的浓度共同决定。本研究报道了两种全新晶体结构：Cu(吡啶)₄TaOF₅与Cu(吡啶)₄TiF₆·3H₂O。
晶体学参数如下：对于Cu(吡啶)₄TaOF₅，属单斜晶系（monoclinic），空间群为C2/c（序号15），晶胞参数a=10.541(3) Å，b=13.547(6) Å，c=16.04(1) Å，β=97.73(5)°，Z=4；对于Cu(吡啶)₄TiF₆·3H₂O，属单斜晶系（monoclinic），空间群为C2/c（序号15），晶胞参数a=12.767(4) Å，b=12.048(2) Å，c=17.787(6) Å，β=109.9(1)°，Z=4。