Synthetic mineral compound, composition including such a compound and method for manufacturing such a compound

A method for preparing a compound of following formula (I):

• At(SixGe1-x)4MzO10(OH)2 (I)
• wherein:
• A is at least one monovalent interfoliary cation of a metal element having the formula Liw(1)Naw(2)Kw(3)Rbw(4)Csw(5);
• wherein each w(i) represents a real number of the interval [0;
• 1], such that Σi=15w(i)=1,
• t is a real number of the interval [0.3;
• 1],
• x is a real number of the interval [0;
• 1],
• M is at least one divalent metal having the formula
• Mgy(1)Coy(2)Zny(3)Cuy(4)Mny(5)Fey(6)Niy(7)Cry(8);
• wherein each y(i) represents a real number of the interval [0;
• 1], such that Σi=18y(i)=1
• z is a real number in the range [2.50;
• 2.85], and
• t+2z is a real number of the interval [5.3;
• 6.0];
• said method comprising:
• preparing a precursor gel of the compound of formula (I) by a co-precipitation reaction between:
• at least one source of at least one chemical element selected from the group consisting of silicon and germanium, said source of the chemical element selected from the group consisting of silicon and germanium being selected from the group consisting of potassium metasilicate and potassium metagermanate,
• at least one metal salt of the divalent metal M,
• the molar proportion (SixGe1-x)/M during the preparation of the precursor gel being in the range [2/1.425;
• 1.6]
• adding at least one hydroxide of formula AOH to the precursor gel so that the molar proportion of A/M is at least equal to t/z, and
• carrying out a solvothermal treatment of the precursor gel at a temperature of between 300° C. and 600° C.