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

Method for preparing a compound of following formula (I):

• At(SixGe1-x)4MzO10(OH)2 (I)
• in which:
• A denotes at least one monovalent interfoliary cation of a metal element, A having the formula Liw(1)Naw(2)Kw(3)Rbw(4)Csw(5);
• Li denoting lithium, Na denoting sodium, K denoting potassium, Rb denoting rubidium, Cs denoting cesium and each w(i) representing a real number of the interval [0;
• 1], such that Σi=18y(i)=1,
• t is a real number of the interval [0.3;
• 1],
• Si denotes silicon,
• Ge denotes germanium,
• x is a real number of the interval [0;
• 1],
• M denotes at least one divalent metal having the formula Mgy(1)Coy(2)Zny(3)Cuy(4)Mny(5)Fey(6)Niy(7)Cry(8);
• Mg denoting magnesium, Co denoting cobalt, Zn denoting zinc, Cu denoting copper, Mn denoting manganese, Fe denoting iron, Ni denoting nickel, and Cr denoting chromium;
• each y(i) representing 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],
• t+2z is a real number of the interval [5.3;
• 6.0]
• O denotes oxygen, and
• H denotes hydrogen.
• said method in which:
• a precursor gel of the compound of formula (I) is prepared 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 chosen 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]
• at least one hydroxide of formula AOH is added to the precursor gel so that the molar proportion of A/M is at least equal to t/z,
• a solvothermal treatment of the precursor gel is carried out at a temperature of between 300° C. and 600° C.