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PaBr4 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Pa4+ is bonded in a 8-coordinate geometry to eight equivalent Br1- atoms. There are four shorter (2.84 Å) and four longer (3.13 Å) Pa–Br bond lengths. Br1- is bonded in a distorted water-like geometry to two equivalent Pa4+ atoms.
PaBr5 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two PaBr5 clusters. Pa5+ is bonded to six Br1- atoms to form edge-sharing PaBr6 octahedra. There are a spread of Pa–Br bond distances ranging from 2.65–2.91 Å. There are five inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Pa5+ atom. In the second Br1- site, Br1- is bonded in a water-like geometry to two equivalent Pa5+ atoms. In the third Br1- site, Br1- is bonded in a single-bond geometry to one Pa5+ atom. In the fourth Br1- site, Br1- is bonded in a single-bond geometry to one Pa5+ atom. In the fifth Br1- site, Br1- is bonded in a single-bond geometry to one Pa5+ atom.
Pa3Br is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Pa sites. In the first Pa site, Pa is bonded to four equivalent Br atoms to form a mixture of distorted edge and corner-sharing PaBr4 cuboctahedra. All Pa–Br bond lengths are 3.19 Å. In the second Pa site, Pa is bonded in a distorted square co-planar geometry to four equivalent Br atoms. All Pa–Br bond lengths are 3.21 Å. Br is bonded to twelve Pa atoms to form a mixture of face, edge, and corner-sharing BrPa12 cuboctahedra.