The synthesis and structural characterization of new hydroxo-fluorometallates [H 3 N(CH 2 ) 6 NH 3 ] 2 M(F,OH) 7 .H 2 O (M=Al, In) are presented. Their preparation is achieved in solvothermal conditions by microwave or classical heating. The isotopic structures, determined by single crystal X-ray diffraction, are triclinic with the space group P-1. The structural arrangement can be described from isolated MX 6 (X=F, OH) octahedra connected by diprotonated diaminohexane via a complex network of hydrogen bonds. X - anions and water molecules are found between the organic chains. A study by 1 9 F NMR of the Al compound confirms a statistical occupancy of fluorine sites by hydroxyl groups and the occurrence of isolated F - anions.