On the Electride Nature of Na-hP4
On the Electride Nature of Na-hP4
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Na-hP4 的电子化合物性质
DOI：
10.1002/ange.202310802
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发表时间：
2023
影响因子：
--
通讯作者：
Racioppi S
中科院分区：
文献类型：
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作者：
Racioppi S
早期的量子力学模型表明，压力驱动固体走向自由电子金属行为，其中离子被锁定在简单的密堆积结构中。高压电子化合物（HPE）是一种开放结构的化合物，其中价电子位于间隙空隙中，其预测和随后的发现需要范式转变。我们对标志性绝缘 Na-hP4 HPE 的量子化学计算表明，由于 1s2s 和 3s 态之间的泡利排斥以及 3pd 态与核心的正交性，密度的增加会导致 3s→3pd 电子跃迁。由此产生的 Na-pd 杂化轨道的大瓣指向 11 元五帽三棱柱的中心并建设性重叠，形成多中心键，这导致了 Na-hP4 中间隙电荷局域化的出现。这些多中心键有助于增加该相的密度，这是其在压力下稳定的关键。
Early quantum mechanical models suggested that pressure drives solids towards free‐electron metal behavior where the ions are locked into simple close‐packed structures. The prediction and subsequent discovery of high‐pressure electrides (HPEs), compounds assuming open structures where the valence electrons are localized in interstitial voids, required a paradigm shift. Our quantum chemical calculations on the iconic insulating Na‐hP4 HPE show that increasing density causes a 3s→3pd electronic transition due to Pauli repulsion between the 1s2s and 3s states, and orthogonality of the 3pd states to the core. The large lobes of the resulting Na‐pd hybrid orbitals point towards the center of an 11‐membered penta‐capped trigonal prism and overlap constructively, forming multicentered bonds, which are responsible for the emergence of the interstitial charge localization in Na‐hP4. These multicentered bonds facilitate the increased density of this phase, which is key for its stabilization under pressure.