STRUCTURE OF ROTATOR PHASES IN NORMAL-ALKANES
STRUCTURE OF ROTATOR PHASES IN NORMAL-ALKANES
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DOI：
10.1021/j100227a032
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发表时间：
1983-01-01
影响因子：
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通讯作者：
UNGAR, G
中科院分区：
文献类型：
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作者：
UNGAR, G
3-5低于熔点。空间群为F？3 m，它有一个六边形的子细胞，而单位细胞延伸通过三个分子层。在最短的烷烃CnH 24中，FCO相中的侧向晶胞参数a0/b 0的比率为1.45-1.47，并且低于有序正交形式（1.49）。然而，在长链烷烃的FCO相中，该比率随温度急剧增加，当a0/b 0接近31/2的六方晶格值时，该增加被加速。在39.5 ~ 41 ℃之间，C23 H4 g中存在另一个以C面为中心的塑性相。在C25 H52中也可以观察到。更高度有序的改性，这出现在C25 H521 -2 K下的过渡到塑性状态，这也是在较长的烷烃中发现的，是由X射线衍射显示为改性B先前描述的C33 H68。
3-5 K below melting point. Its space group is f? 3m and it has a hexagonal subcell, while the unit cell extends through three molecular layers. In the shortest paraffin, CnH24, the ratio of lateral unit-cell parameters a0/b0 in the FCO phase is 1.45-1.47 and is lower than in the ordered orthorhombic form (1.49). However, in the FCO phase of longer alkanes this ratio increases steeply with temperature, the increase being accelerated as a0/b0 approaches the hexagonal lattice value of 31/2. Another C-face-centered plastic phase is present in C23H4g between 39.5 and 41 C. It is also observed in C25H52 on cooling. The more highly ordered modification, which appears in C25H521-2 K below the transition into the plastic state, and which is also found in longer alkanes, is shown by X-raydiffraction to be the modification B previously described in C33H68.