The solid-state compounds CsTh2Se6, Rb0.85U1.74S6, RbU2Se6, TIU2Se6, Cs-0.88(La0.68U1.32)Se-6, KNP2Se6, and CsNp2Se6 of the AAn(2)Q(6) family (A = alkali metal or TI; An = Th, U, Np; Q = S, Se, Te) have been synthesized by high-temperature techniques. All seven crystallize in space group lmmm of the orthorhombic system in the KTh2Se6 structure type. Evidence of long-range order and modulation were found in the X-ray diffraction patterns of TIU2Se6 and CsNp2Se6. A 4a X 4b supercell was found for TIU2Se6 whereas a 5a x 5b x 5c supercell was found for CsNp2Se6. All seven compounds exhibit Q-Q interactions and, depending on the radius ratio R-An/R-A1 disorder of the A cation over two sites. The electrical conductivity of RbU2Se6, measured along [100], is 6 x 10(-5) S cm(-1) at 298 K. The interatomic distances, including those in the modulated structure of TIU2Se6, and physical properties suggest the compounds may be formulated as containing tetravalent Th or U, but the formal oxidation state of Np in the modulated structure of CsNp2Se6 is less certain. The actinide contraction from Th to U to Np is apparent in the interatomic distances.