The extraction mechanism of At is inferred as following:The complex-anions AtX2-(X = Cl-, Br-, I-, OH-) were formed, mainly in aqueous solutions and paired with the cations M+(M=H+, K+, Na+), then the ion pair was extracted by crown ethers .

• At在溶液中主要形成络合阴离子AtX_2-(X=CI~-,Br~-,I~-,OH~-),它与适宜的阳离子M~+(M=H~+,K~+,Na~+)配成离子对被冠醚所萃取,这是At被萃取的主要形式,萃取反应简单表示为:M~++C_(有)+AtX_2~-(?)