Crystal Structure of a-Fluorine
Crystal Structure of a-Fluorine
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α-氟的晶体结构
DOI：
10.1063/1.1670323
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发表时间：
1968
期刊：
影响因子：
--
通讯作者：
S. C. Greer
中科院分区：
文献类型：
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作者：
L. Meyer;C. Barrett;S. C. Greer
用X射线粉末衍射法研究了在45.6K以下稳定的α-氟的晶体结构。α氟是单斜晶系，可能是C2 / m空间群，但不能完全排除C2 / c空间群。每个单位细胞有四个分子。在23°K时，晶胞尺寸为：a = 5.50 ± 0.01A，b = 3.28 ± 0.01A，c = 10.01 ± 0.01A，β = 134.66° ± 0.02°。在23°K下的晶胞体积为128.4 a3，计算密度为1.97g/cm~3，摩尔体积为19.3cm~3/摩尔。其结构与α-O2非常相似，主要区别在于分子倾斜，在交替的层中，可能只有11°左右的垂直于基面的交替侧，导致与α-O2相比，c方向的晶胞加倍。单胞包含四个分子的事实承认了C2 / c空间群的可能性，分子倾斜出了ac平面。
The crystal structure of α‐fluorine, stable below 45.6°K, has been investigated from x‐ray powder‐diffraction patterns. Alpha fluorine is monoclinic, probably space group C2 / m, but space group C2 / c cannot be ruled out completely. There are four molecules per unit cell. At 23°K, the cell dimensions are: a = 5.50 ± 0.01 A, b = 3.28 ± 0.01 A, c = 10.01 ± 0.01 A, β = 134.66° ± 0.02°. The unit‐cell volume at 23°K is 128.4 A3, the calculated density is 1.97 g/cm3, and the calculated molar volume is 19.3 cm3/mole. The structure is very similar to α‐O2, the main difference being that the molecules are tilted, probably only by about 11° to alternate sides of the normal to the basal plane in alternate layers, leading to a doubling of the unit cell in the c direction as compared to α‐O2. The fact that the unit cell contains four molecules admits the possibility of space group C2 / c with the molecules tilted out of the ac plane.