Hydrothermal synthesis of prismatic NaHoF4 microtubes and NaSmF4 nanotubes

A new example of tubular materials based on sodium rare-earth tetrafluorides, NaHoF4 and NaSmF4, has been fabricated by a simple hydrothermal method. In addition, an unusual nanotube with a perfect couple of an outer prismatic shell with an inner concentric prismatic nanorod at the center is found. According to the architectures of various products, the general growth mechanism of these tubes is proposed.