Mercury(ii) Bromide Paper

Mercuric bromide paper

In a rectangular dish place a 50 g/L solution of mercuric bromide in anhydrous ethanol and immerse in it pieces of white filter paper weighing 80 g per square metre (speed of filtration = filtration time expressed in seconds for 100 mL of water at 20° with a filter surface of 10 cm² and constant pressure of 6.7 kPa: 40 seconds to 60 seconds), each measuring 1.5 cm by 20 cm and folded in two. Allow the excess liquid to drain and allow the paper to dry, protected from light, suspended over a non-metallic thread. Discard 1 cm from each end of each strip and cut the remainder into 1.5 cm squares or discs of 1.5 cm diameter.

Store in a glass-stoppered container wrapped with black paper.