"There is a remarkable agreement between the polarization of Raman spectra involving O-H (O-D) stretching vibrations and the calculated intensity. "The Raman spectrum of water in natural natrolite in Fig. exhibits two main O-H bands at ν1 = 3331 cm -1 and ν3 = 3542 cm -1 and several additional bands of smaller intensity, which can be combined in two doublets at ν'1 = 3187, ν'3 = 3385 and ν"1 = 3226, ν"3 = 3473 cm -1 . These two doublets can be ascribed to vibration of H2O molecules located in two additional sites in the crystal, W' and W'', with approximate relative occupancy of about 5% with respect to that of the main W site, which is almost completely occupied. This assumption is supported by the chemical composition of natural natrolite, which shows an excess of water of at least 1.5 % (or 0.03 H2O per ideal 2 H2O formula unit)" . , studied the "behavior of H2O molecules in the channels of natrolite and scolecite", by means of single-crystal polarized Raman spectra and IR spectroscopy. "Both IR and Raman spectra show intense O-H stretching and H2O bending modes derived from the hydrogenbonded H2O molecule(s) in the channels. Using published crystal structural data for natrolite and scolecite, and a consideration of Raman mode intensities that are sensitive to the H2O orientation in the framework channels, the internal stretching and bending modes could be assigned" . "The stretching vibrations of H2O molecules of natrolite and scolecite are located between 3200 and 3700 cm -1 and bending vibrations occur around 1650 cm -1 . In the case of natrolite, two intense O-H stretching modes can be observed and also several weaker combination modes. … For scolecite, six O-H stretching modes are observed in the Raman spectra recorded at 4 K, but only five are found at room temperature in the IR or Raman" . In Kolesov and Geiger we can find crystal structures, with occluded H2O of natrolite and scolecite. In natrolite, the H2O molecules and Na cations are placed in the channel cavities. Na cations are in the center of the channel, whereas the H2O molecules are located closer the walls of the channel. In the Fig, For what is regarding natrolite, "Two intense O-H stretching modes are observed in the IR and Raman spectra of natrolite. The low-wavenumber mode at ~3320 cm -1 represents to a large degree the motion of the more strongly H-bonded hydrogen atom of the H2O molecule. The high-wavenumber band at ~3540 cm -1 is related to an O-H mode related to the moreweakly H-bonded hydrogen atom. The former mode derives from the ν1 mode of a free symmetric H2O molecule and the latter from the asymmetric vibration, ν3" . "The band at 3469 cm -1 in the Raman bbspectrum at room temperature … is separated from the intense Ow-H1 stretching band at ~3320 (3324 cm -1 at room temperature) by 146 cm -1 . The band at 3179 cm -1 … appears in both Raman and IR spectra at temperatures greater than 80 K … and is separated from the band at 3320 cm -1 by approximately the same value, 144 cm -1 , but is located at lower energies. Thus, interpret these two weak Raman bands as Stokes (3469 cm -1 ) and anti-Stokes (3179 cm -1 ) counterparts of the same combination mode … . Note that the band at 3469 cm -1 is not a single combination mode. A deconvolution into Lorentzian components produces weak features at approximately 3369, 3392, 3426, and 3495 cm -1 … in the unpolarized Raman and IR spectra" (See the further discussion in . Therefore, we have bands given at: 3179, 3324, 3369, 3391, 3426, 3495 cm -1 .