Published online by Cambridge University Press: 16 February 2011
The formation of lithium inserted W18O49 phases has been studied byelectrochemical methods. When lithium is inserted, several single phases LixW18O49 are observed in the range 0 ≤ x ≤ 40 between 3 and 1 V. Nevertheless the reaction is reversible only for x ≤ 22. Chemical reactions of W18O49 with different quantities of n-butyllithium have been carried out to isolate and characterize some of these phases. For Li17W18O49, this is ˜1:1 Li/W ratio, electron diffraction experiments clearly indicate that lithium produces a periodicity change, doubling the a, b and c cell parameters. On the other hand, when sodium is inserted in W18O49 two single phase regions NaxW18O49 are observed within the range 0 ≤ x ≤ 1.2 between 3 and 0.5 V.