We present a detailed study of B-1 N-x(x) (0 < x < 0.6) films synthesized at room temperature by N-2(+) ion-beam assisted evaporation of boron. The atom-ion ratio was related to the final boron concentration as determined by X-ray energy dispersive spectroscopy (XEDS), and to the bonding structure explored by infrared (IR) and X-ray absorption near-edge structure (XANES) spectroscopies. IR and XANES revealed that N-rich boron nitrides had a graphite-like structure with embedded nitrogen molecules, while B-rich boron nitrides consisted of different ratios of B13N2/h-BN phases. Our spectroscopic results indicate that this B13N2 structure is made of B-12 icosahedral units linked by N-B-N linear chains. (C) 2011 Elsevier B. V. All rights reserved.