Rotational constants B and C, centrifugal distortion constants Delta(J) and Delta(JK), and nuclear hyperfine coupling constants are determined for four isotopomers of nitryl bromide from their rotational spectra. Experimental nuclear quadrupole coupling constants are interpreted to provide information about the N-Br bond and are compared with those from electronic structure calculations. (c) 2007 Elsevier B.V. All rights reserved.