text: Lanthanum oxide can crystallize in at least three polymorphs.
  Hexagonal  has been produced by spray pyrolysis of lanthanum chloride.
  An alternative route to obtaining hexagonal  involves precipitation of nominal  from aqueous solution using a combination of 2.5%  and the surfactant sodium dodecyl sulfate followed by heating and stirring for 24 hours at 80 °C:
  Other routes include: