Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo, 152-8551, Japan.
NMR Station, National Institute for Materials Science (NIMS), 3-13 Sakura, Tsukuba, Ibaraki, 305-0003, Japan.
Nat Commun. 2023 Apr 24;14(1):2337. doi: 10.1038/s41467-023-37802-4.
The chemical order and disorder of solids have a decisive influence on the material properties. There are numerous materials exhibiting chemical order/disorder of atoms with similar X-ray atomic scattering factors and similar neutron scattering lengths. It is difficult to investigate such order/disorder hidden in the data obtained from conventional diffraction methods. Herein, we quantitatively determined the Mo/Nb order in the high ion conductor BaNbMoO by a technique combining resonant X-ray diffraction, solid-state nuclear magnetic resonance (NMR) and first-principle calculations. NMR provided direct evidence that Mo atoms occupy only the M2 site near the intrinsically oxygen-deficient ion-conducting layer. Resonant X-ray diffraction determined the occupancy factors of Mo atoms at the M2 and other sites to be 0.50 and 0.00, respectively. These findings provide a basis for the development of ion conductors. This combined technique would open a new avenue for in-depth investigation of the hidden chemical order/disorder in materials.
固体的化学有序和无序对材料性能有决定性的影响。有许多材料表现出具有相似 X 射线原子散射因子和相似中子散射长度的原子的化学有序/无序。用传统的衍射方法从所获得的数据中研究这种隐藏的有序/无序是困难的。在此，我们通过结合共振 X 射线衍射、固态核磁共振（NMR）和第一性原理计算的技术，定量确定了高离子导体 BaNbMoO 中的 Mo/Nb 有序。NMR 提供了直接的证据，证明 Mo 原子仅占据在本质上氧不足的离子导体层附近的 M2 位。共振 X 射线衍射确定 Mo 原子在 M2 和其他位置的占有率分别为 0.50 和 0.00。这些发现为离子导体的开发提供了基础。这种组合技术将为深入研究材料中的隐藏化学有序/无序开辟新的途径。
