 It is a crystalline substance.Caesium pentanitratoaluminate has been formed by treating a mixture of caesium chloride and caesium tetracloroaluminate with dinitrogen tetroxide and methyl nitrate, and pumping off the NOCl gas produced.If only caesium tetracloroaluminate is used, omitting the CsCl, then the result contains solid Al(NO3)3·CH3CN as well.