The title compounds were prepared by direct reactions of the corresponding elements at high temperature. They are isostructural with each other (monoclinic, P2(1)/m, Z = 2; Na8BaPb6, a = 13.116(4), b = 5.351(l), and c = 16.166(5) Angstrom, = 108.07(2)degrees; Na8BaSn6, a = 12.897(4), b = 5.362(l), and c = 16.826(5) Angstrom, beta = 108.19(2)degrees; Na8EuSn6, a 12.912(2), b = 5.220(1), and c = 15.721(2) Angstrom, beta = 108.09(1)degrees) and contain isolated, flat, and aromatic pentagonal rings of Sn-5(6-) and Pb-5(6-) as well as isolated anions of Sn4- and Pb4-. According to four-probe conductivity measurements, the tin compounds, Na8BaSn6 and Na8EuSn6, are semiconducting with band gaps of 0.11 and 0.09 eV, respectively, and are therefore electronically balanced. Magnetic measurements show that Na8BaSn6 is diamagnetic while Na8EuSn6 is paramagnetic and undergoes two transitions at low temperatures.