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Novel flowerlike NH4LnFx (Ln =Er, Tm, Yb,Lu) hierarchical architectures have been tailor-made under controlled proper reaction conditions via an "ion-exchange assisted crystallization" route.The hierarchical architecture is assembled by NH4LnFx nanosheets.We found that the amount of NH4, F and the temperature of ion-exchange reaction are crucial to the formation of the flowerlike structure.The effects of the amount of NH,F and the temperature of ion-exchange reaction have been thoroughly investigated.The experimental results indicated that excess NH4F and low reaction temperature (e.g.30 ℃, 50 ℃) can result in the formation of nanocages products, while proper amount of NH4F and high reaction temperature (e.g.70 ℃) favor the formation of flowerlike products.