#IUPAC

The legendary traffic lights in Berlin, the “Ampelmännchen”, symbolise the opposite biological functions of chromium compounds in two major oxidation states: one for health and the other for disease. In other words, green stands for “go and safe”, red stands for “stop and danger”.

Most people know that uranium is radioactive, but few would think of taking a Geiger Counter with them when antique-hunting. A hundred years ago, uranium oxide was widely used in making decorative glass objects. Their characteristic greenish-yellow colour gave them the name of ‘Vaseline glass’, though their radioactivity means that uranium is not used in glass-making these days. Uranium is also used in making the shells fired by Army tanks, as it is extremely dense and also tends to ignite on impact.