Helical Polymer 1/∞[P2Se62-]: Strong Second Harmonic Generation Response and Phase-Change Properties of Its K and Rb Salts
Helical Polymer 1/∞[P2Se62-]: Strong Second Harmonic Generation Response and Phase-Change Properties of Its K and Rb Salts
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DOI：
10.1021/ja075096c
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发表时间：
2007-11
影响因子：
15
通讯作者：
I. Chung;C. Malliakas;J. I. Jang;C. Canlas;D. Weliky;M. Kanatzidis
中科院分区：
文献类型：
--
作者：
I. Chung;C. Malliakas;J. I. Jang;C. Canlas;D. Weliky;M. Kanatzidis
A2P2Se6(A=K，Rb)在298(2)K和a=14.4916(7)A，c=18.7999(17)A，Z=3的手性三角空间群P3121中结晶，对于K+盐，a=7.2982(5)A，c=19.0019(16)A，在100(2)K，Z=3。A2P2Se6具有平行的一维螺旋链1/∞[P2Se62-]，它描述了类乙烷的[P2Se6]4-阴离子的氧化聚合。当冷却温度远低于室温时，K2P2Se6表现出向晶体亚群的位移相变，并形成晶胞沿a轴和b轴加倍的超结构。Rb类似物没有发生相变。化合物是空气稳定的，表现出可逆的玻璃-晶体相变行为，K+和Rb+盐的禁带红移分别为0.11和0.22 eV。用拉曼光谱、31P魔角旋转固体核磁共振和对分布函数(PDF)的分析，给出了晶态和玻璃态K2P2Se6的电子结构.
The selenophosphates A2P2Se6 (A = K, Rb) crystallize in the chiral trigonal space group P3121, with a = 7.2728(9) A, c = 18.872(4) A, and Z = 3 at 298(2) K and a = 14.4916(7) A, c = 18.7999(17) A, and Z = 12 at 173(2) K for K+ salt and a = 7.2982(5) A, c = 19.0019(16) A, and Z = 3 at 100(2) K for Rb+ salt. The A2P2Se6 feature parallel one-dimensional helical chains of 1/∞[P2Se62-] which depict an oxidative polymerization of the ethane-like [P2Se6]4- anion. On cooling well below room temperature K2P2Se6 exhibits a displacive phase transition to a crystallographic subgroup and forms a superstructure with a cell doubling along the a- and b-axes. The Rb analogue does not exhibit the phase transition. The compounds are air stable and show reversible glass-crystal phase-change behavior with a band gap red shift of 0.11 and 0.22 eV for K+ and Rb+ salts, respectively. Raman spectroscopy, 31P magic angle spinning solid-state NMR, and pair distribution function (PDF) analysis for crystalline and glassy K2P2Se6 give...