Low-temperature synthesis of novel metal oxides by topochemical reactions

Novel metal oxides were prepd. at low temps. by topochem. reactions. Topochem. dehydration of $Mo1- \times W \times O_3.H_2O$ provides a convenient route for the prepn. of $Mo1-\timesW\timesO3$ in ReO\times3-type structure. Dehydration of $HMoO_2PO_4.H_2O$ to $HMoO_2PO_4$ results in a topotactic transformation of the parent chain structure to a layered structure in the product. Exchange of Li with protons in $LiNbWO_6$ and $LiTaWO_6$ results in a novel structural transformation from the rutile to the $ReO_3$ structure of the product phases, $HNbWO_6$ and $HTaWO_6$. Topotactic redn. of LaNiO3 and LaCoO3 yields new vacancy-ordered perovskite-related phases, $La_2Ni_2O_5$ and $La_2Co_2O_5$ that cannot be prepd. otherwise. H can be inserted topotactically into $LaNiO_3$ and $LaCoO_3$ around ambient temps. in the presence of Pt-catalyst to yield $HxLaNiO_3$ and $HxLaCoO_3$. Insertion of Bi into $WO_3$ yielding intergrowth W bronzes, $BixWO_3$, can also be viewed as a topotactic process