TY - JOUR
T1 - An infrared spectroscopic study of the OH stretching frequencies of talc and 10-Å phase to 10 GPa
AU - Parry, Stephen A.
AU - Pawley, Alison R.
AU - Jones, Ray L.
AU - Clark, Simon M.
PY - 2007/4
Y1 - 2007/4
N2 - The effects of pressure on the OH stretching frequencies of natural talc and two samples of synthetic 10-Å phase have been measured using a diamond-anvil cell and a synchrotron infrared source. The 10-Å phase was synthesized at 6.0-6.5 GPa, 600 °C for 46 hours (sample 10Å-46) and 160 hours (10Å-160). Spectra were collected up to 9.0 GPa (talc), 9.9 GPa (10Å-46), and 9.6 GPa (10Å-160). The OH stretching vibration of Mg3OH groups in talc occurs at 3677 cm-1 at ambient pressure, and increases linearly with pressure at 0.97(2) cm-1 GPa-1. The same vibration occurs in 10-Å phase, but shows negligible pressure shift up to 2 GPa, above which the frequency increases linearly to the maximum pressure studied, at a rate of 0.96(3) cm-1 GPa-1 (10Å-46) and 0.87(3) cm-1 GPa-1 (10Å-160). Two other prominent bands in the 10-Å phase spectrum are suggested to be due to stretching of interlayer H2O, hydrogen-bonded to the nearest tetrahedral sheet. These bands also show little change over the first 2 GPa of compression, as most of the compression of the structure is taken up by closing non-hydrogen bonded gaps between interlayer H2O and tetrahedral sheets. Between 2 and 4 GPa, changes in band intensities suggest a rearrangement of the interlayer H2O.
AB - The effects of pressure on the OH stretching frequencies of natural talc and two samples of synthetic 10-Å phase have been measured using a diamond-anvil cell and a synchrotron infrared source. The 10-Å phase was synthesized at 6.0-6.5 GPa, 600 °C for 46 hours (sample 10Å-46) and 160 hours (10Å-160). Spectra were collected up to 9.0 GPa (talc), 9.9 GPa (10Å-46), and 9.6 GPa (10Å-160). The OH stretching vibration of Mg3OH groups in talc occurs at 3677 cm-1 at ambient pressure, and increases linearly with pressure at 0.97(2) cm-1 GPa-1. The same vibration occurs in 10-Å phase, but shows negligible pressure shift up to 2 GPa, above which the frequency increases linearly to the maximum pressure studied, at a rate of 0.96(3) cm-1 GPa-1 (10Å-46) and 0.87(3) cm-1 GPa-1 (10Å-160). Two other prominent bands in the 10-Å phase spectrum are suggested to be due to stretching of interlayer H2O, hydrogen-bonded to the nearest tetrahedral sheet. These bands also show little change over the first 2 GPa of compression, as most of the compression of the structure is taken up by closing non-hydrogen bonded gaps between interlayer H2O and tetrahedral sheets. Between 2 and 4 GPa, changes in band intensities suggest a rearrangement of the interlayer H2O.
UR - http://www.scopus.com/inward/record.url?scp=34247332170&partnerID=8YFLogxK
U2 - 10.2138/am.2007.2211
DO - 10.2138/am.2007.2211
M3 - Article
AN - SCOPUS:34247332170
SN - 0003-004X
VL - 92
SP - 525
EP - 531
JO - American Mineralogist
JF - American Mineralogist
IS - 4
ER -