Two-dimensional composition diagram of the Al(OH)3-dien-HFaq.-ethanol system:: Evidence of a new tetrahedral (Al4F18)6- polyanion

Six domains appear in the 21) composition diagram of the Al(OH)(3)-dien-HFaq.-ethanol system at 190 degrees C and [Al3+] = 1 mol L-1 under microwave heating. Four organic-inorganic fluorides crystallise: [H(3)dien](.)(AlF6) (P2(1)/c, Z = 4), [H(3)dien](2).(AlF5(H2O))(3)center dot 2H(2)O (P2(1)/4, Z = 4), [H(3)dien]center dot(AlF6)center dot 2H(2)O, which was previously known, and [H(3)dien](2)center dot(Al4F18) (C2/c, Z = 4). A new (Al4F18)(6-) polyanion, which results from the tetrahedral association of four AlF6 octahedra linked by corners, is evidenced in [H(3)dien](2)center dot(Al4F18). (c) 2006 Elsevier B.V. All rights reserved.