I was preparing a solution of Strontium Chloride by reacting Strontium Carbonate powder with some dilute Hydrochloric acid. As expected, the acid reacted with the SrCO3 and began to fizzle (Carbon Dioxide forming in a similar reaction to vinegar and baking soda). I began to detect a slight odor in the air and, upon further inspection, it was coming from the SrCO3 + HCl reaction taking place. I wafted it a bit, it smelled a little like it had some Sulfur in it and it had the “rotten egg” smell. The only gas/gasses being produced in the reaction was/were colorless. What could have caused this Sulfury odor? Does it have something to do with the Strontium? Or perhaps is it an impurity in the SrCO3?