X-ray diffraction study of ${\mathrm{Na}}_{1/3}$${\left({\mathrm{H}}_2\mathrm{O}\right)}_{1.5}$${\mathrm{TaS}}_2$: Observation of a Hendricks-Teller disordered layer lattice

Powder x-ray diffraction data for the layered cointercalation compound ${\mathrm{Na}}_{1/3}$ ${\left({\mathrm{H}}_2\mathrm{O}\right)}_{1.5}$ ${\mathrm{TaS}}_2$ exhibit a pronounced oscillation in the basal-plane reflection linewidths with diffraction order. The origin and period of this oscillation are derived on simple physical grounds. The linewidths and positions are quantitatively modeled by using the theory of Hendricks and Teller. This analysis shows that the structure contains a random stacking sequence of ${\mathrm{H}}_2$O monolayers and bilayers between the ${\mathrm{TaS}}_2$ layers.