Dissolve 67.58g FeCl3.6H2O in 250ml of

2M HCl.

Dissolve 39.76g FeCl2.4H2O in 100ml of

2M HCl.

Ferrofluids 1

Modified from Berger et al, Journal of Chemical Education, 1999, 26, 7, 943-948

1M FeCl3 should be used within one week of

preparation.

2M FeCl2 should be used within one week of

preparation.

Ferrofluids 2

Combine 3ml of FeCl2 solution and 12ml of

FeCl3 solution and fill a burette with 150ml of

0.7M ammonium hydroxide solution.

Add ammonia very slowly whilst stirring. A

black precipitate of magnetite will form.

Ferrofluids 3

After addition is complete, stop stirring

and use a strong magnet (Nd2Fe12B) to settle the black precipitate to the

bottom of the flask.

Decant off the water and add fresh water. Rinse

the precipitate and again decant off the water. Repeat three times to

remove excess ammonia.

Ferrofluids 4

Transfer the viscous liquid to a weighing boat using a little extra water

if necessary. Use a magnet on the base of the weighing boat to remove excess water.

Add 24ml of tetramethylammonium

hydroxide (25% solution) and stir with a glass rod

Ferrofluids 5

Hold a magnet on the base of the weighing boat and let the solid settle to the bottom.

Decant off any excess liquid to leave a very viscous black liquid.

The viscous liquid should form spikes if a magnet is held underneath the

weighing boat. You may need to adjust the amount of water.

Ferrofluids 6