The hexagonal boron-nitride 'nanomesh' surface reconstruction on Rh(111) [Corso et al., Science 303 (2004) 217-220] has been investigated using surface X-ray diffraction utilizing synchrotron radiation. This unique structure has been found to be stable under ambient atmosphere which provides an important basis for technological applications like templating and coating. The previously suggested (12 x 12) periodicity of this reconstruction has been unambiguously confirmed and structural features are discussed in the light of the X-ray diffraction results. (c) 2006 Elsevier B.V. All rights reserved.