English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Spectroscopic (micro FTIR, Raman, MAS NMR) and mass spectroscopic techniques have been used to examine, on both single-crystal and powder samples, the behavior of H 2 O and CO 2  molecules in the structural channels of an alkali-poor, volatile-rich beryl from Brazil. Polarized single-crystal FTIR and Raman spectra were obtained on oriented wafers of isolated crystals. Location and orientation of H 2 O and CO 2  molecules were determined from IR spectra. The proton-proton vectors of type-I and type-II H 2 O are parallel and perpendicular to the c axis, respectively; the molecular axis of the CO 2   molecule is perpendicular to the c axis. Relative proportions of both types of H 2 O were determined from their respective IR absorption-band intensities and were found to be nearly equivalent. There is, contrary to what is generally claimed in the literature, no relation between alkali and type-II H 2 O contents. Absorptivity coefficients for H 2 O and CO 2  were computed for every specific orientation. A  1 H MAS NMR spectrum resolved as a “Pake” doublet seems to confirm the absence of any anisotropic movement of the H 2 O molecules from one orientation to the other on the NMR time scale. Mass discrimination of volatiles released by pyrolysis under vacuum confirms the weak mobility of H 2 O and CO 2  molecules in the channel sites, although the plugging effect of alkalis in the channels can be neglected for such an alkali-poor beryl. The volatile vs. alkali content ratio in beryl could possibly be used as an environmental indicator.

Channel occupancy in an alkali-poor beryl from Serra Branca (Goias, Brazil): Spectroscopic characterization