CEROUS OXALATE 285product of the decomposition, of cerous oxalate, is readily oxidized
by the oxygen of the air to eerie oxide, CeO 2. In contact with
the air therefore eerie oxide is the stable oxide. The salts of
eerie oxide, however, are in general not stable and go over rather
easily to cerous salts. This is particularly true of eerie chloride,
CeCU, which decomposes spontaneously into cerous chloride,
CeCl 3 , and free chlorine.
Materials: Crude CeO 2 ,22.2 grams = 0.1 F.W. + 5 grams.
12iVHCl,34cc. = 0.4 F.W.
oxalic acid, H 2 C 2 O4-2H 2 O, 20 grams.
3 N sodium carbonate,
ammonium oxalate solution.
Apparatus: 2-liter common bottle.
300-cc. flask.. 5-inch funnel.
8-inch porcelain dish.
400-cc. beaker,
suction filter and trap bottle,
iron ring and ring stand.
Bunsen burner.
Procedure: Dilute 34 cc. of 12N HC1 to 50 cc. and pour it into
the 300-cc. flask. Add the eerie oxide under a hood. Warm
gently until the reaction starts. Stop heating until the reaction
slows down, then heat cautiously to boiling and keep at that tem-
perature for 5 minutes. Cool; filter without suction directly into
the large bottle. Dilute to 700 cc. The iron is now to be pre-
cipitated as Fe(OH) 3. Add 5 cc. of 3 N Na 2 CO 3. If the precipi-
tate is light colored, showing that it consists in the main of white
cerous carbonate, no more Na 2 CO 3 need be added, otherwise add
3-cc. portions of this reagent until the new precipitate shows no
brownish color of ferric hydroxide (best let the precipitate settle
and pour some of the nearly clear liquid into a beaker in order
that the color may be observed when the reagent is added).
Stir the whole suspension in the bottle and let it settle. Decant
the clear liquid through the filter directly into an 8-inch evap-
orating dish, finally pouring the sludge on to the filter and letting
it drain. Add 5 cc. of 12N HC1 to the filtrate; boil down to
75-100 cc. Pour into the beaker. Dissolve the oxalic acid in