Spektor Kristina, Crichton Wilson A, Filippov Stanislav, Simak Sergei I, Fischer Andreas, Häussermann Ulrich
ESRF, The European Synchrotron Radiation Facility, F-38000 Grenoble, France.
Theoretical Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping, Sweden.
Inorg Chem. 2020 Nov 16;59(22):16467-16473. doi: 10.1021/acs.inorgchem.0c02294. Epub 2020 Nov 3.
The formation of ternary hydrogen-rich hydrides involving the first-row transition metals TM = Fe and Co in high oxidation states is demonstrated from in situ synchrotron diffraction studies of reaction mixtures NaH-TM-H at 10 GPa. NaFeH and NaCoH feature pentagonal bipyramidal FeH and octahedral CoH 18-electron complexes, respectively. At high pressure, high temperature (300 < ≤ 470 °C) conditions, metal atoms are arranged as in the face-centered cubic Heusler structure, and ab initio molecular dynamics simulations suggest that the complexes undergo reorientational dynamics. Upon cooling, subtle changes in the diffraction patterns evidence reversible and rapid phase transitions associated with ordering of the complexes. During decompression, NaFeH and NaCoH transform to tetragonal and orthorhombic low pressure forms, respectively, which can be retained at ambient pressure. The discovery of NaFeH and NaCoH establishes a consecutive series of homoleptic hydrogen-rich complexes for first-row transition metals from Cr to Ni.
通过对10 GPa下反应混合物NaH-TM-H进行原位同步辐射衍射研究,证明了涉及高氧化态第一行过渡金属TM = Fe和Co的三元富氢氢化物的形成。NaFeH和NaCoH分别具有五角双锥FeH和八面体CoH 18电子配合物。在高压、高温(300 < ≤ 470 °C)条件下,金属原子按面心立方休斯勒结构排列,从头算分子动力学模拟表明配合物经历了重排动力学。冷却时,衍射图样的细微变化证明了与配合物有序化相关的可逆且快速的相变。减压过程中,NaFeH和NaCoH分别转变为四方和正交的低压形式,它们可以在常压下保留。NaFeH和NaCoH的发现为从Cr到Ni的第一行过渡金属建立了一系列连续的同配富氢配合物。