Fig. 5.
Solid state EPR spectra of μ-Qz-syn crystal recorded at −196 ° C: as-grown (a), as milled (b), 3 days after milling (c), and 1 month after milling (d). The spectra were recorded with: sweep width 100 G, receiver gain 1 × 104, microwave power 0.1 mW (a very low potency at which the silyl radical is visible and not saturated, while all the other silico-oxygen radical features are hardly visible), scan time 80 s. Mechanical fracturing of as-grown μ-Qz-syn introduced radical defects (b), absent on the pristine quartz crystal (a). Two components (g//and gx) of the signal relative to silyl radicals were detected. Silyl radicals were stable for three (c) and decreased 30 days after milling (d)