Sodium Nitrite: Chile Saltpetre Melted with Lead

Sodium nitrite cures meat and makes the diazo compounds behind azo dyes. One way to make it: melt sodium nitrate and stir lead into it. The lead takes oxygen from the nitrate and becomes litharge, leaving nitrite. A few grams of nitrite can kill, and lead is a poison too: label everything and keep it away from food. The picture: sodium nitrite crystals in a jar.