Nitrogen and oxygen guest molecules in clathrate hydrates: different sites revealed by Raman spectroscopy

N2 and O2 hydrates (clathrates) from a polar ice core (Vostok) were analysed by high‐sensitivity Raman microspectrometry. Three new lines in the region of the stretching modes of N2 and O2 guest molecules were observed and were interpreted by considering both small (512) and large (51264) cages in type II clathrates, isotopic effects and the possibility of double occupancy of the large cages. The isotopic effect for N2 and O2 guest molecules in clathrates is demonstrated. © 1997 John Wiley & Sons, Ltd.