Fellow chemists, I am looking for a possible chemical explanation and safety concerns regarding a solution of barium azide in water that has turned orange.  Why?

The solution of 100 gm of barium azide in 300 gm water (Pfaltz and Bauer solution) was decanted into approximately 6 smaller, vacuum-sealed bottles about 4 years ago.  All solutions have been kept stored in a cabinet the whole time; i.e., they have not been exposed to light.  The solution has now turned orange.  There is no precipitate, and the seals appear to be intact.  Has anyone experienced something similar?  Any ideas for why it has turned orange, and whether or not that is hazardous are appreciated.

Sonja

Sonja G. Ringen

Occupational Health and Safety Specialist

National Institute of Standards and Technology

325 Broadway, MC 173.02

Boulder, CO  80305-3337

Office: 303-497-7389

Cell:  303-961-9251