High-pressure synthesis and crystal structures of molybdenum nitride Mo3N5 with anisotropic compressibility by a nitrogen dimer
High-pressure synthesis and crystal structures of molybdenum nitride Mo3N5 with anisotropic compressibility by a nitrogen dimer
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氮二聚体高压合成具有各向异性压缩性的氮化钼Mo3N5及其晶体结构
DOI：
10.1039/d2dt03433f
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发表时间：
2023
影响因子：
4
通讯作者：
Hasegawa Masashi
中科院分区：
文献类型：
--
作者：
Sasaki Takuya;Yamamoto Takuro;Asano Shuto;Niwa Ken;Hasegawa Masashi
使用激光加热金刚石砧池在高压下通过钼与氮的氮化反应在 45 GPa 以上合成了一种新型高压氮化钼相 Mo3N5。 Mo3N5具有N-N二聚体和7配位Mo位点，以空间群为Cmcm（No.63）的斜方结构结晶，没有其他原型结构。 Mo3N5 的精化晶格参数为 a = 2.86201(2) Å、b = 7.07401(6) Å 和 c = 14.59687(13) Å。 DFT 焓计算表明 Mo3N5 是高压稳定相，这也与与环境压力和低压相相比配位数增加一致。通过压缩曲线拟合，确定Mo3N5的零压体积模量为K0 = 328(4) GPa，K′0 = 10.1(6)，与理论E-V曲线和弹性刚度常数几乎一致。 Mo3N5的压缩性具有与晶体结构中N-N二聚体方向相对应的轴向各向异性。
A novel high-pressure molybdenum nitride phase, Mo3N5, was synthesized at above 45 GPa via a nitridation reaction of molybdenum with nitrogen under high pressure using a laser-heated diamond anvil cell. Mo3N5, having an N–N dimer and 7-coordinated Mo sites, crystallizes in an orthorhombic structure with a space group of Cmcm (No. 63) without other prototype structures. The refined lattice parameters for Mo3N5 were a = 2.86201(2) Å, b = 7.07401(6) Å, and c = 14.59687(13) Å. The DFT enthalpy calculation suggested that Mo3N5 is a high-pressure stable phase, which is also consistent with an increasing coordination number compared to ambient- and low-pressure phases. The zero-pressure bulk modulus of Mo3N5 was determined to be K0 = 328(4) GPa with K′0 = 10.1(6) by the fitting for the compression curve, which is almost consistent with the theoretical E–V curve and elastic stiffness constants. The compressibility of Mo3N5 has axial anisotropy corresponding to the N–N dimer direction in the crystal structure.