Negative Linear Compressibility and Massive Anisotropic Thermal Expansion in Methanol Monohydrate
Negative Linear Compressibility and Massive Anisotropic Thermal Expansion in Methanol Monohydrate
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DOI：
10.1126/science.1198640
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发表时间：
2011-02-11
期刊：
影响因子：
56.9
通讯作者：
Knight, Kevin S.
中科院分区：
文献类型：
--
作者：
Fortes, A. Dominic;Suard, Emmanuelle;Knight, Kevin S.
绝大多数材料在流体静力压缩时在所有方向上收缩;例外情况包括某些金属或聚合物泡沫结构，其可能表现出负线性压缩性（NLC）（即，它们在流体静力压缩下在一个或多个方向上膨胀）。在分子水平上表现出这种性质的材料-具有内在NLC的结晶固体-是非常罕见的。利用中子粉末衍射，我们发现并表征了简单分子晶体（氘代甲醇和水的1：1化合物）中的非线性液晶和极端各向异性的热膨胀，包括沿非线性液晶轴的负热膨胀（NTE）沿着。由羟基-水链与甲基桥连形成的顶端连接的菱形沿NLC/NTE轴沿着延伸并导致所观察到的行为。
The vast majority of materials shrink in all directions when hydrostatically compressed; exceptions include certain metallic or polymer foam structures, which may exhibit negative linear compressibility (NLC) (that is, they expand in one or more directions under hydrostatic compression). Materials that exhibit this property at the molecular level-crystalline solids with intrinsic NLC-are extremely uncommon. With the use of neutron powder diffraction, we have discovered and characterized both NLC and extremely anisotropic thermal expansion, including negative thermal expansion (NTE) along the NLC axis, in a simple molecular crystal (the deuterated 1:1 compound of methanol and water). Apically linked rhombuses, which are formed by the bridging of hydroxyl-water chains with methyl groups, extend along the axis of NLC/NTE and lead to the observed behavior.