H(3)tren (3+) and H(4)tren (4+) fluoride zirconates or tantalates
Résumé
Four new [H(3)tren](3+) or [H(4)tren](4+) fluoride zirconates and two new [H(3)tren](3+) fluoride tantalates are evidenced in the (ZrF4 or Ta2O5)-tren-HFaq.-ethanol systems at 190 degrees C: the structurally related phases [H(4)tren]center dot(Zr2F12)center dot H2O and alpha-[H(4)tren](center dot)(Zr2F12) (P2(1)2(1)2(1)). beta-[H(4)tren]center dot(Zr2F12) (P2(1/c)), [H(3)tren](4)center dot(ZrF8)(3)center dot 4H(2)O (123). beta-[H(3)tren](2)center dot(Ta3O2F16)center dot(F) (R32) and its monoclinic distortion alpha-[H(3)rren](2)center dot(Ta3O2F16)center dot(F) (C2/m). alpha and beta-[H(4)tren]center dot(Zr2F12) and [H(4)tren]center dot(Zr2F12)center dot H2O are built up from (Zr2F12) dimers of edge sharing ZrF7 polyhedra while isolated ZrF8 dodecahedra are found in [H(3)tren](4)center dot(ZrF8)(3)center dot 4H(2)O. Linear (Ta3O2F16) trimers build et and beta-[H(3)tren](2)center dot(Ta3O2F16)center dot(F); they consist of two (TaOF6) pentagonal bipyramids that are linked to two opposite oxygen atoms of one central (TaO2F4) octahedron. A disorder affects the equatorial fluorine atoms of the trimers and eventually carbon or nitrogen atoms of [H(3)tren](3+) cations. (C) 2011 Elsevier B.V. All rights reserved.