Phosphonic acids alkaline earth metal complexes

Polyamino polyalkyl phosphonic acids have been investigated as potential complexors for alkaline earth metal complexes. Ligands investigated include nitrilotrimethylphosphonates (70),360 phosphoryl derivatives of polyamines (71)361 and monoalkylphosphonic acids.362 They show complexing capability towards Be2+, Mg24-, Ca2+, Sr24" and Ba, but are not as efficient... 

Ion chromatography can be used for the determination of ionic solutes such as inorganic anions, inorganic cations (including alkali metals, alkaline earth metals, transition metals, and rare earth metals), carboxylic, phosphonic and sulfonic acids, detergents, carbohydrates, low molecular weight organic bases, and ionic metal complexes. 

In a number of transition metal complexes, the coordination modes of dialkyl H-phospho-nates correspond to a, b, or e in the above scheme. The coordination mode c is characteristic for silver, alkaline, and earth-alkaline metals. Coordination of type d is encountered in molecular complexes of dialkyl H-phosphonates with Lewis acids as well as in some nontransition and early transition metals as discussed further in the text. 

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