We have measured a nuclear spin conversion time of 100 min for H2O highly diluted in solid xenon at 4.2 K. Compared with argon matrices, the conversion is very probably enhanced by the high natural abundance of xenon magnetic isotopes. The nu(2) mode absorption spectrum of rare gas isolated H2O, with polymerization and rotation translation coupling effects, is still debated. In this work, the nu(2) IR absorption spectrum of H2O in xenon is compared to that observed in neon, argon and krypton matrices. A new assignment of the rovibrational lines is proposed, demonstrated using the nuclear spin conversion studies. (C) 2009 Elsevier B.V. All rights reserved.