Reactions of Pr turnings, PrBr3, and metallic Z in Nb containers at 780-910-degrees-C yield Pr6Br10Z (Y6I10Ru type) for Z = Co, Ru, Os, monoclinic Pr3Br3Ru (Pr3I3Ru type), and cubic Pr3Br3Z (Ca3PI3 type) for Z = Co, Os, Rh, Ir, Pt. Other Z elements investigated yield the binary Pr2Br5 or unknown phases. The structures of Pr6Br10Co and Pr6Br10Ru have been refined (P1BAR; Z = 1; a = 9.359(4), 9.206(4) angstrom, b = 9.243(5), 9.505(3) angstrom, c = 7.538(3), 7.606(4) angstrom, alpha = 97.37(4), 97.08(4)-degrees, beta = 107.31(4), 107.47(4)-degrees, gamma = 110.17(3),109.69(4)-degrees, R = 4.3, 5.2%, R(w) = 3.8, 6.7%, respectively). The tetragonal compression in the 16-electron Pr6Br10Ru (0.28 angstrom in d(Pr-Ru)) is notably greater than observed in the analogous Y6I10Ru, probably because of reduced matrix effects (repulsions) between the smaller bromide components. Earlier theoretical predictions regarding a one-over-two splitting of the parent t1u4 in the idealized octahedral iodide are therefore supported. The 17-electron Pr6Br10Co shows a possibly related compression of 0.12 angstrom.