Hexahydrated cations

Difference hexahydrated cations (table 2.5) and reference [3] glasses (basalt B and granite G)... 

Aqueous solutions of basic aluminum salts, especially basic aluminum chloride, are the most commonly used aluminum precursors. Depending on the synthesis conditions, different species are observed in the solutions [11] [21]. The monomeric hexahydrated cation, [Al (H20)6f is stable only In highly acidic solution. At an OH/AI molar ratio of 3, AI(OH)3 is formed and precipitated whereas at lower ratios, i.e., 2 to 2.5, polymeric species such as the complex pseudo-spherical cation [Al O4 Ali2(0H)24(H20)i2], also referred to as the AIm cation, and larger polymeric species are formed. 

In Table 2 are collected some characteristic Y NMR chemical shifts. Nowadays, a common reference compound for Y NMR is aqueous Y(N03)s although aqueous YCI3 also has been used. In fact, both salts form, in water, the same hexahydrate cation, [Y(H20)g]. Generally, the chemical shifts of the yttrium salts show similar concentration trends to those observed for scandium and lanthanum. 

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