ERA-Chemistry: Searching for ultra-incompressible materials: Formation and characterisation of binary and ternary period 6 transition metal borides at very high pressures and temperatures

定向寻找超不可压缩化合物的一种方法是基于这样的想法，即高价电子密度与共价键的结合应该提供具有所需性质的化合物。这导致了对含有第六周期的重过渡金属离子（Ta、W、Re、Os、Ir）和轻元素（如碳、氮或硼）的化合物的广泛研究。这些化合物中的一些，例如OsB 2，确实显示出优异的物理性能，但是一些被认为是非常有前途的化合物，例如B：Re比> 2的硼氢化物，还没有被合成。众所周知，高压/高温条件可能导致不寻常的粘合环境和新的结构类型。然而，我们的知识的高压行为的二元周期6过渡金属硼化物是相当有限的。虽然相应的碳化物和氮化物被很好地研究，但还没有在极端p，T条件下原位合成硼化物的研究，因此我们对二元和三元第6周期过渡金属硼化物的p，T相稳定性的了解非常有限。因此，目前的建议集中在理解相关系，结构和性能的二元和三元周期6过渡金属硼化物在非常高的压力和温度下获得的激光加热金刚石砧单元和大容量的高压设备，补充机械化学活化合成与高速球磨和密度泛函理论为基础的原子模型计算。将用多种技术对样品进行鉴定，包括微量热法、振动光谱法和同位素富集化合物的中子衍射法。该项目充分利用了因斯布鲁克和法兰克福的互补专业知识和可用的实验设备，并有望产生新的化合物，更深入地了解硼化物的晶体化学，并可能合成具有优异性能的材料。

One approach for the directed search for ultra-incompressible compounds is based on the idea that acombination of a high valence electron density in conjunction with covalent bonds should providecompounds with the desired properties. This has led to an extensive search for compounds containingheavy transition metal ions of period 6 (Ta,W,Re,Os,Ir) and a light element, such as carbon, nitrogen orboron. Some of these compounds, such as OsB2, have indeed shown outstanding physical properties, but several compounds, which are thought to be very promising, such as a rhenium boride with a B:Re ratio > 2, have not been synthesized yet. It is well established that high pressure/high temperature conditions may lead to unusual bonding environments and new structure types. However, our knowledge of the high pressure behavior of binary period 6 transition metal borides is rather limited. While the corresponding carbides and nitrides are well investigated, no in-situ synthesis studies of borides at extreme p,T-conditions have been published yet and hence our knowledge of the p,T-phase stabilities of binary and ternary period 6 transition metal borides is extremely limited. Hence, the current proposal focusses on understanding phase-relations, structures and properties of binary and ternary period 6 transition metal borides obtained at very high pressures and temperatures in laser heated diamond anvil cells and large-volume high pressure devices, complemented by mechanochemically activated synthesis with high speed ball milling and density functional theory based atomistic model calculations. Samples will be characterized by numerous techniques, including microcalorimetry, vibrational spectroscopy and neutron diffraction on isotopically enriched compounds. The project fully exploits the complementary expertise and available experimental equipment in Innsbruck and Frankfurt and promises to yield novel compounds, a deeper understanding of the crystal chemistry of borides and possibly a route to synthesize materials with outstanding properties.