Americium and europium extraction by synergistic mixture of 2,6-bis(1-aryl-1H-tetrazol-5-yl)pyridines (ATP) - chlorinated cobalt dicarbollide (CCD) in polar diluents from HNO₃ media was studied. Metanitrobenzotrifluoride, phenyltrifluoromethyl sulfone and 1,2-dichloroethane were used as diluents. The effect of diluent, composition of aqueous phase and substituent nature in aryl ring of ATPs on the extraction efficiency and selectivity of americium and europium separation was investigated. At the optimal ratio of nATP:CCD = 1:1 the Am - Eu separation factor exceeded 90. Extraction of ⁸⁵Sr, ¹³⁷Cs and ¹³³Ba was investigated and it was found that the mixture nATP-CCD provided the separation of Sr /Ba pair with a factor of 35. High resistance of 2,6-bis-aryltetrazolyl pyridines to the action of nitric acid was demonstrated.