A Mg-rich palygorskite sample from phosphorite deposits of Ganntour (Morocco) with the structural formula Si8(Mg2.6Al1.19Fe0.33III0.88)Ca0.056Na0.024K0.104O20(OH)2(OH2)4·4H2O, was studied by FTIR spectroscopy. In both OH-stretching and OH-bending regions, there is evidence of dioctahedral Al2□OH, AlFe□OH and trioctahedral Mg3OH features, leading to a di-trioctahedral crystallochemical model of octahedral site occupancies in ribbons of Ganntour palygorskite.

This model, established through the IR spectroscopy study of a Mg-rich palygorskite, seems to be appropriate for many other palygorskites with lower Mg content in the octahedral sheet.

You do not currently have access to this article.