Cation site distribution in clinochlores: a NIR approach

Abstract

Abstract A near infrared (NIR) spectroscopy approach was undertaken to collect information on the Al cationic distribution in tetrahedral and octahedral sites in natural chlorite (clinochlore) samples. Structural formulae were established using electron microprobe and Mössbauer spectroscopy. A band located near 7115 cm –1 was attributed to the overtone of OH fundamental stretching mode of Mg 2 AlOH and increases with the total Al amount. Good correlation was obtained between the (SiAl)O–OH vibration band area and tetrahedral Al content, making it easy to partition Al (and thus Fe 3+ ) between octahedral and tetrahedral sites.