Weigh directly into a 100-mL erlenmeyer flask 0.7 g of chromium(III)
chloride hexahydrate (CrCl3 2
A6H O) and dissolve it in 25 mL distilled
water. Weigh out 3 g urea and add it in 3 or 4 portions to the deep green
chromium solution, stirring well after each addition. Then add 1.75 mL
of acetylacetone drop-wise, using a pipette. Clamp the flask in a boiling
water bath and heat the mixture while stirring for approximately one
hour. The solution should initially be very dark and almost black in
appearance, but as the reaction proceeds, deep maroon plate-like crystals
form as a crust on the surface of the reaction mixture.