A study of the hydration of the alkali metal ions in aqueous solution.
A study of the hydration of the alkali metal ions in aqueous solution.
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DOI：
10.1021/ic2018693
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发表时间：
2012-01-02
影响因子：
4.6
通讯作者：
Persson I
中科院分区：
文献类型：
--
作者：
Mähler J;Persson I
用大角度X射线散射(LAXS)和双差红外光谱(DDIR)研究了碱金属离子在水溶液中的水化过程。测定了二甲基亚砜溶剂化碱金属离子在溶液中的结构，以支持在水溶液中的研究。LAXS和DDIR测量结果表明，钠、钾、Rb和Cs离子都是弱水化的，只有一层水分子。较小的锂离子水合程度更高，很可能存在第二个水合壳。Rb和Cs离子对水结构的影响很小，由于结合在这些金属离子上的部分氚水的O-D伸缩带和主体水的O-D伸缩带没有充分分离，所以不可能可靠地量化这种影响。用LAXS研究了钠、钾和铯的水溶液以及铯和氢氧化锂的水溶液，除锂外，已相当准确地测定了M-O键距。然而，由于距离数与温度因子密切相关，因此很难从LAXS测量中确定与碱金属离子结合的水分子的数目。从现有的结构数据库中对配体通过氧键合的固体碱金属化合物的M-O键距离进行了全面的分析。碱金属离子的M-O键距与配位数之间也有较强的相关性，尽管M-O相互作用较弱，具有明确配位几何构型的钾、锶、铯的络合物很少。测定了水合钠离子、钾离子、铋离子和铯离子在水溶液中的平均M-O键距分别为2.43(2)，2.81(1)，2.98(1)和3.07(1)，对应于六、七、八和八配位。这些配位数得到了水化热和M-O键距的线性关系的支持。这个关联式表明，水合锂离子在水溶液中是四配位的。对于四配位和六配位锂(I)，分别为0.60和0.79；对于五和六配位钠(I)，分别提出了新的离子半径：1.02和1.07。六坐标和七坐标K+的离子半径分别为1.38和1.46；八坐标Rb+和Cs+的离子半径分别为1.64和1.73；二甲基亚砜溶液中钠、钾、锶、铯等离子的M-O键距离与水溶液中观察到的M-O键距离非常相似。用大角度X射线散射、激光X-射线散射和双差红外光谱研究了碱金属离子的水化过程。并与相应的晶体结构进行了比较，得出了水溶液中水化数的结论，并提出了新的离子半径。提出了钠、钾、锶、铯离子在水溶液中的水化数为6、7、8和8。
The hydration of the alkali metal ions in aqueous solution has been studied by large angle X-ray scattering (LAXS) and double difference infrared spectroscopy (DDIR). The structures of the dimethyl sulfoxide solvated alkali metal ions in solution have been determined to support the studies in aqueous solution. The results of the LAXS and DDIR measurements show that the sodium, potassium, rubidium and cesium ions all are weakly hydrated with only a single shell of water molecules. The smaller lithium ion is more strongly hydrated, most probably with a second hydration shell present. The influence of the rubidium and cesium ions on the water structure was found to be very weak, and it was not possible to quantify this effect in a reliable way due to insufficient separation of the O–D stretching bands of partially deuterated water bound to these metal ions and the O–D stretching bands of the bulk water. Aqueous solutions of sodium, potassium and cesium iodide and cesium and lithium hydroxide have been studied by LAXS and M–O bond distances have been determined fairly accurately except for lithium. However, the number of water molecules binding to the alkali metal ions is very difficult to determine from the LAXS measurements as the number of distances and the temperature factor are strongly correlated. A thorough analysis of M–O bond distances in solid alkali metal compounds with ligands binding through oxygen has been made from available structure databases. There is relatively strong correlation between M–O bond distances and coordination numbers also for the alkali metal ions even though the M–O interactions are weak and the number of complexes of potassium, rubidium and cesium with well-defined coordination geometry is very small. The mean M–O bond distance in the hydrated sodium, potassium, rubidium and cesium ions in aqueous solution have been determined to be 2.43(2), 2.81(1), 2.98(1) and 3.07(1) Å, which corresponds to six-, seven-, eight- and eight-coordination. These coordination numbers are supported by the linear relationship of the hydration enthalpies and the M–O bond distances. This correlation indicates that the hydrated lithium ion is four-coordinate in aqueous solution. New ionic radii are proposed for four- and six-coordinate lithium(I), 0.60 and 0.79 Å, respectively, as well as for five- and six-coordinate sodium(I), 1.02 and 1.07 Å, respectively. The ionic radii for six- and seven-coordinate K+, 1.38 and 1.46 Å, respectively, and eight-coordinate Rb+ and Cs+, 1.64 and 1.73 Å, respectively, are confirmed from previous studies. The M–O bond distances in dimethyl sulfoxide solvated sodium, potassium, rubidium and cesium ions in solution are very similar to those observed in aqueous solution. The hydration of alkali metal ions has been studied by large angle X-ray scattering, LAXS, and double difference infrared spectroscopy. The obtained M−O bond distances from LAXS have been compared to relevant crystal structures, conclusions about hydration numbers in aqueous solution have been made, and new ionic radii have been proposed. Hydration numbers of six, seven, eight and eight are proposed for the sodium, potassium, rubidium and cesium ions in aqueous solution.
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影响因子：
4.6
作者：
BERGSTROM, PA;LINDGREN, J
通讯作者：
LINDGREN, J
影响因子：
--
作者：
BERGSTROM, PA;LINDGREN, J;KRISTIANSSON, O
通讯作者：
KRISTIANSSON, O
影响因子：
3.8
作者：
Bouazizi, Salah;Nasr, Salah
通讯作者：
Nasr, Salah
影响因子：
2.9
作者：
Azam, S. Sikander;Hofer, Thomas S.;Rode, Bernd M.
通讯作者：
Rode, Bernd M.
DOI：
10.1039/dt9810002105
发表时间：
1981-01-01
期刊：
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
影响因子：
--
作者：
BEATTIE, JK;BEST, SP;WHITE, AH
通讯作者：
WHITE, AH