New rare-earth silicide oxides, La10Si8O3 (1) and Ce10Si8O3 (2), were synthesized through high-temperature reactions of the pure elements under controlled oxygen atmosphere conditions. The remarkable silicides crystallize in a unique crystal structure (space group P6/mmm; a = 10.975(3) angstrom (La) and 10.844(1) angstrom (Ce); c = 4,680(1) angstrom (La) and 4.561 (1) angstrom (Ce)) that features a 3-D framework of corner-shared O-centered (La/Ce)(6) octahedra, reminiscent of hexagonal tungsten bronzes, with planar Si-6 rings enclosed within its hexagonal channels, Band structure calculations indicate the compounds are metallic, with optimized La-Si bonds, and a benzene-like [Si-6](6-) anion. Compound 1 exhibits temperature independent paramagnetism. Compound 2 exhibits Curie-Weiss paramagnetism, and an antiferromagnetic ordering below 7 K.