Effect of composition on charge exchange, lattice expansion, and staging in potassium-ammonia graphite intercalation compounds.
Effect of composition on charge exchange, lattice expansion, and staging in potassium-ammonia graphite intercalation compounds.
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钾氨石墨插层化合物中成分对电荷交换、晶格膨胀和分级的影响。
DOI：
10.1103/physrevb.31.8206
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Solin
中科院分区：
文献类型：
--
作者：
York;Solin
研究了1级碱-氨三元石墨插层化合物K (nh3) x cy（0≤x≤4.33,12≤y≤24）夹层厚度的电荷交换和组分依赖关系。提出了一个三明治能量模型，该模型明确地说明了x依赖的电荷交换和尺寸或刚度效应，并且与（00l） x射线衍射模式对氨蒸气压的依赖性的实验测量结果非常吻合。从这个模型中我们发现，对于阶段1的化合物K (nh3) 4.33 c24, f= 0.95，并且nh3分子溶解了一些电子电荷，这些电子电荷最初是在kc24起始材料中给予碳层的。此外，nh3分子形成平面四配位的K (nh3) 4簇，因此也溶剂化了石墨廊中的K+离子。我们认为，K (nh3) 4簇与“间隔”nh3分子一起构成了已被充分研究的大块三维金属-氨溶液的二维结构类似物。
We have studied the charge exchange and compositional dependence of the sandwich thickness of stage-1 alkali-ammonia ternary graphite intercalation compounds K (NH 3) x C y, 0≤ x≤ 4.33, 12≤ y≤ 24. A model of the sandwich energy is presented which explicitly accounts for x-dependent charge exchange and size or stiffness effects and is in excellent agreement with experimental measurements of the dependence of the (00l) x-ray diffraction patterns on ammonia vapor pressure. From this model we find that for the stage-1 compound K (NH 3) 4.33 C 24, f= 0.95 and that the NH 3 molecules solvate some of the electron charge which was originally donated to the carbon layers in the KC 24 starting material. In addition, the NH 3 molecules form planar fourfold-coordinated K (NH 3) 4 clusters and hence also solvate the K+ ions in graphite galleries. We suggest that the K (NH 3) 4 clusters together with ‘‘spacer’’NH 3 molecules constitute the two-dimensional structural analog of the well-studied bulk, three-dimensional metal-ammonia solutions.