The nanoscroll-to-nanotube thermal transformation was studied for H4Nb₆O₁₇∙4.4H₂O scrolls, prepd. by exfoliation of K₄Nb₆O₁₇. Thermal dehydration of the scrolls produces Nb₂O₅ nanotubes at 400-450˚C The nontopochem. transformation results in polycryst. nanotubes; however, significant texturing with respect to the tube axis is obsd. Substituting Ta for Nb in the precursor compd. led to a lower yield of scrolls, most likely because there is less built-in lattice strain to drive scrolling of the unilamellar colloidal sheets. [on SciFinder(R)]