Reflection spectrum Solid state - transformation

The solid-state MSi NMR spectrum of talc displays a single resonance at -98.5 ppm [24], Upon, VA1 substitution, the wSi chemical shift value is shielded (more positive ppm value), whereas further distortion of the tetrahedral sheet is reflected in a decreased chemical shift value (deshielded, increased negative ppm value). The authors of this report suggest that solid-state wSi NMR may be used to determine the compositional nature of phyllosilicate minerals. In each of these studies, the spectra were obtained at a frequency of 71.5 MHz on a Fourier transform spectrometer interfaced to a 8.45-T magnet. Tetramethylsilane (TMS) was used as an external chemical-shift standard. 

The Fourier transform-infrared (FT-IR) spectra of two polymorphs, an amorphous form and a methanol solvate of a hydrochloride salt, are shown in Figure 3.24 (see Figure 3.17 for the corresponding DSC thermograms). The spectra can be used to give information on how the molecule is packed in the solid state and which groups of the molecule are in a different environment. As can be seen, the spectrum of the amorphous form of the compound is less well defined and reflects the multitude of molecular environments present in this form of the compound. 

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