Complex sentence: When protected from light and moisture thionyl chloride has a long shelf life, however the material is know to slowly age on storage, developing a yellow hue, possibly due to the formation of disulfur dichloride.
Split into simpler sentences: When protected from light and moisture thionyl chloride has a long shelf life. The material is know to slowly age on storage, developing a yellow hue, possibily due to the formation of disulfur dichloride.