The invention concerns a IM-11 crystalline solid with structure type LTA, with a neutral framework, having a chemical composition expressed as the anhydrous base in terms of moles of oxide defined by the general formula XO.sub.2:mYO.sub.2:qR:sF, in which R represents one or more nitrogen-containing organic compounds, X represents one or more tetravalent elements other than germanium, Y represents germanium, F is fluorine, m, q, s represent the number of moles of YO.sub.2, R and F respectively, m is in the range 0.1 to 4, and q and s are in the range 0 to 1.