Interstellar silicates are a major component of interstellar
dust. Their properties, such as the composition, size distribution of
dust grains and internal structure, are important components in many
astrophysical models. The infrared and X-ray part of the spectrum
provide important tools to understand and constrain these properties.
In the soft X-ray band, we can use the unique features in the absorption edges of Si, O, Fe and Mg in the spectra of X-ray binaries to analyse silicates in various environments in the Galaxy, where X-ray binaries serve as background sources to probe the intervening dust along the line of sight. I will present the results of 9 sightlines towards X-ray binaries located in the Central Galactic environment. The study profits from new dust models derived from new laboratory measurements of interstellar dust analogues.
The features around 10 and 20 micron in infrared spectra of various sources can also be used to study silicates. I will highlight the possibility of studying the properties of nano silicates using these features. Nano grains may provide insight into the formation of grains in the interstellar medium (ISM), since the observation of these small clusters may point to active grain formation in the ISM. They may also explain the absence of crystalline dust in ISM, since many atoms are near the surface of the grain, distorting the lattice structure, which may make the grains appear amorphous while they are still in their lowest energy configuration.