Compositional dependence of negative thermal expansion in the Prussian blue analogues MIIPtIV(CN)6 (M = Mn, Fe, Co, Ni, Cu, Zn, Cd)
Compositional dependence of negative thermal expansion in the Prussian blue analogues MIIPtIV(CN)6 (M = Mn, Fe, Co, Ni, Cu, Zn, Cd)
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DOI：
10.1021/ja060916r
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发表时间：
2006-05-31
影响因子：
15
通讯作者：
Kepert, Cameron J.
中科院分区：
文献类型：
--
作者：
Chapman, Karena W.;Chupas, Peter J.;Kepert, Cameron J.
用变温粉末X射线衍射（100-400 K）研究了M-II取代对一系列普鲁士蓝类似物（MPtIV）-Pt-II（CN）（6）（M-II = Mn，Fe，Co，Ni，Cu，Zn，Cd）的负热膨胀（NTE）行为的影响。NTE行为随着MII取代而变化很大，从NiPt（CN）（6）的接近零的热膨胀（α = dIII dT = -1.02（11）x 10（-6）K-1）到CdPt（CN）（6）的最大值（α = -10.02（11）x 10（-6）K-1）。随着M-II离子的原子序数（Z）的增加，NTE行为的幅度的趋势遵循顺序Mn-II > Fe-II > Co-II > Ni-II < Cu-II >Zn-II > Cd-II，这与MII阳离子尺寸、晶格参数和结构柔性的趋势相关，如温度依赖性结构细化和拉曼光谱所示。的平均结构的温度依赖性的分析表明，在热膨胀的差异主要是由于不同的强度的金属-氰化物结合相互作用，因此，不同的能量的横向振动的氰化物桥，增强NTE行为更灵活的晶格。
The effect of M-II substitution on the magnitude of the negative thermal expansion (NTE) behavior within a series of Prussian Blue analogues, (MPtIV)-Pt-II(CN)(6) for M-II = Mn, Fe, Co, Ni, Cu, Zn, Cd, has been investigated using variable-temperature powder X-ray diffraction (100-400 K). The NTE behavior varies widely with MII substitution, from near zero thermal expansion in NiPt(CN)(6) (alpha = dIII dT = -1.02(11) x 10(-6) K-1) up to a maximum in CdPt(CN)(6) (alpha = -10.02(11) x 10(-6) K-1). The trend in the magnitude of the NTE behavior, with increasing atomic number (Z) of the M-II ion, follows the order Mn-II > Fe-II > Co-II > Ni-II < Cu-II > Zn-II > Cd-II, which correlates with the trends for MII cation size, the lattice parameter, and structural flexibility as indicated by the temperature-dependent structural refinements and Raman spectroscopy. Analysis of the temperature dependence of the average structures suggests that the differences in the thermal expansion are due principally to the different strengths of the metal-cyanide binding interaction and, accordingly, the different energies of transverse vibration of the cyanide bridge, with enhanced NTE behavior for more flexible lattices.