Syntheses and Structures of the Tungstoborate Anions

Autor: Monique Michelon, Gilbert Herve, Andre Teze
Rok vydání: 1997
Předmět:
Zdroj: Inorganic Chemistry. 36:505-509
ISSN: 1520-510X
0020-1669
DOI: 10.1021/ic961051t
Popis: A new tungstoboric species, [BW13O46H3]8-, which was identified in solution, is an intermediate between [BW11O39H]8- and the so-called hexagonal acid. This heteropolyacid was obtained in high yield by a new synthetic route. A single-crystal X-ray diffraction study showed that its formula is H21[B3W39O132]·69H2O. The heteropolyanion is formed by three BW13O46 subunits linked together by sharing vertices leading to C3h symmetry. Each subunit is constituted by a undecatungstic anion derived from the Keggin structure, capped by a μ-oxoditungstic group, W2O11. The BO4 tetrahedron is significantly distorted, one of the B−O bonds being longer (1.58 A) than the three others (1.46 A). The conversions between the three species [BW11O39H]8-, [BW13O46H3]8- and [B3W39O132]21- are rapid and reversible. On the contrary, the irreversible formation of the Keggin heteropolyanion, α-[BW12O40]5-, is observed by heating of the solution of [BW13O46H3]8- at pH 1−5.
Databáze: OpenAIRE