Dioctahedral 2:1 phyllosilicates and process for their preparation.

摘要

1. Crystallised dioctahedral 2:1 phyllosilicates, characterised by: a) the following approximate general chemical formula (for a half unit cell): M<m+><H N=0>x/m((Si(4-x)Tx)(T2@1)O10(OH(2-y)Fy))<x->. nH2O - where T represents an element chosen from the IIIA group and iron, - where M is at least one cation of valency compensation m, - where x is a number of between 0 and 2; y is a number of between 0 and 2, and n is a positive number or zero. b) a X-ray diffraction diagram comprising at least the following lines: - a line at 1.49 +/- 0.01 x 10<-10> m or at 1.52 +/- 0.01 x 10<-10> m - two lines at 4.46 +/- 0.02 x 10<-10> m and 2.56 +/- 0.015 x 10<-10> m or at 4.55 +/- 0.02 x 10<-10> m and at 2.60 +/- 0.015 x 10<-10> m - at least one 001 reflection such that d001 is 12.5 +/- 3 x 10<-10> m c) a fluorine content such that the molar ratio F<->/Si is of between 0.1 and 4, d) at least one signal at -133 ppm (+/- 5 ppm) in the NMR, magic-angle spinning, of the <19>F, the said phyllosilicates having been synthesised in a fluorinated medium in the presence of HF acid and at a pH below 9.