A monoclinic crystal structure was found by X-ray diffraction for bis[pyridinium tetrabromoferrate(III)]-pyridinium bromide. The double salt contains two slightly distorted [FeBr4]- tetrahedra, three pyridinium rings, and an uncoordinated halide in each asymmetric unit, as is characteristic of the A3Fe2X9 series of compounds. Unit cell parameters, monoclinic space group P2(1), are a = 7.656(3) angstrom, b = 14.237(5) angstrom, c = 13.725(5) angstrom, beta = 93.42(3)degrees, and V = 1493(1) angstrom3, Using Mo Kalpha radiation (lambda = 0.710 69 angstrom), rho(calc) = 2.38 g cm-3, and Z - 2. The tetrahedra are aligned with their 3-fold axes parallel to the crystallographic c axis. Bond lengths (Fe-Br) range froin 2.271(9) angstrom to 2.379(90 angstrom for the two different slightly distorted tetrahedral units. Magnetic susceptibility studies show that the material orders three-dimensionally at 7.4 +/- 0.2 K. The data are compared to a HTS expansion of 1/chi for the S = 5/2 three-dimensional Heisenberg model antiferromagnet for a sc lattice with g = 1.98 and J/k(B) = -0.43 K. The specific heat measurements indicate two odd-shaped lambda features, at 7.3 and 8 K.