Playford Helen Y, Bull Craig L, Tucker Matthew G, Funnell Nicholas P, Ridley Christopher J, Marshall Kenneth P, Walton Richard I
STFC ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, UK.
Dalton Trans. 2017 Nov 14;46(44):15415-15423. doi: 10.1039/c7dt03370b.
The formation of the spin-ice pyrochlore HoGeO by two different high temperature, high pressure routes has been explored using in situ neutron diffraction. The first route involves the solid-state reaction of HoO and GeO, and formation of the pyrochlore phase is observed at 994(27) °C and 3.81(2) GPa, which are significantly milder conditions than those previously reported. The second route involves the hydrothermal synthesis of the tetragonal HoGeO pyrogermanate from Ho(NO)·5HO and GeO and its subsequent transformation to the pyrochlore phase, which is observed at 683(23) °C and 3.89(3) GPa. The lowering of the formation temperature of high pressure phases by employment of a precursor of appropriate stoichiometry may also have applications in the wider field of solid-state chemistry.
利用原位中子衍射研究了通过两种不同的高温高压途径形成自旋冰烧绿石 HoGeO 的过程。第一种途径涉及 HoO 和 GeO 的固态反应，在 994(27) °C 和 3.81(2) GPa 下观察到烧绿石相的形成，这些条件比之前报道的要温和得多。第二种途径涉及由 Ho(NO)·5HO 和 GeO 水热合成四方 HoGeO 焦锗酸盐及其随后向烧绿石相的转变，在 683(23) °C 和 3.89(3) GPa 下观察到这种转变。通过使用适当化学计量比的前驱体来降低高压相的形成温度，这在更广泛的固态化学领域也可能有应用。
