Near-infrared spectroscopic study of basic aluminum sulfate and nitrate
Near-infrared spectroscopic study of basic aluminum sulfate and nitrate
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DOI：
10.1023/a:1004860118470
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发表时间：
2001-02-01
影响因子：
4.5
通讯作者：
Frost, RL
中科院分区：
文献类型：
--
作者：
Kloprogge, JT;Ruan, H;Frost, RL
通过Al 3+的强制水解至OH/Al摩尔比为2.2来制备十三聚体Al-聚合物[AlO 4Al 12（OH）（24）（H2O）（12）]（7+）。在缓慢蒸发条件下，Al-13-硝酸盐形成晶体。加入硫酸盐后，十三聚体结晶为单斜晶系Al（1）3-硫酸盐。这些晶体已经使用近红外光谱进行了研究，并与Al-2（SO 4）（3）进行了比较。16H（2）O.尽管Al-13-硫酸盐和硝酸盐的近红外光谱非常相似，表明晶体结构相似，但结晶水分子与盐基团结合的强度存在微小差异。结晶水与硝酸盐之间的相互作用比与硫酸盐之间的相互作用更强，这反映在结晶水带位置从Al-13硫酸盐的6213、4874和4553 cm（-1）向硝酸盐的5925、4848和4532 cm（-1）的位移。Al-13中的水分子从硫酸根的5079和5037 cm（-1）向硝酸根的5238和5040 cm（-1）的反向位移表明，由于结晶水对硝酸根的影响，硝酸根-Al-13键被削弱。Al-13络合物中的Al-OH键不受改变盐基的影响，这是由于Al-13络合物中的水分子的屏蔽。(C)2001 Kluwer Academic Publishers.
The tridecameric Al-polymer [AlO4Al12(OH)(24)(H2O)(12)](7+) was prepared by forced hydrolysis of Al3+ up to an OH/Al molar ratio of 2.2. Under slow evaporation crystals were formed of Al-13-nitrate. Upon addition of sulfate the tridecamer crystallised as the monoclinic Al(1)3-sulfate. These crystals have been studied using near-infrared spectroscopy and compared to Al-2(SO4)(3 .)16H(2)O. Although the near-infrared spectra of the Al-13-sulfate and nitrate are very similar indicating similar crystal structures, there are minor differences related to the strength with which the crystal water molecules are bonded to the salt groups. The interaction between crystal water and nitrate is stronger than with the sulfate as reflected by the shift of the crystal water band positions from 6213, 4874 and 4553 cm(-1) for the Al-13 sulfate towards 5925, 4848 and 4532 cm(-1) for the nitrate. A reversed shift from 5079 and 5037 cm(-1) for the sulfate towards 5238 and 5040 cm(-1) for the nitrate for the water molecules in the Al-13 indicate that the nitrate-Al-13 bond is weakened due to the influence of the crystal water on the nitrate. The Al-OH bond in the Al-13 complex is not influenced by changing the salt group due to the shielding by the water molecules of the Al-13 complex. (C) 2001 Kluwer Academic Publishers.