An Open Framework Aluminophosphate with Unique 12-Membered Ring Channels: Al9(PO4)12(C24H91N16)·17H2O

This paper reports a new observation of the abnormal reduction of Eu3+Eu2+ in Sr2B5O9Cl when prepared in air at high temperature. A model based on the nature of substitution defects is proposed to explain this abnormal reduction. Electrons, which reduced the Eu3+ ions, are created by the substitution of cations first and then transferred to the target Eu3+ ions via tetrahedral borate anion groups. Codoping experiments are designed and performed. The results of these experiments support the model proposed.