Cerium(IV) hydroxide

Cerium(IV) hydroxide, also known as ceric hydroxide, is an inorganic compound with the chemical formula Ce(OH)4. It is a yellowish powder that is insoluble in water but soluble in concentrated acids.

Production
Cerium(IV) hydroxide can be produced by reacting cerium(III) carbonate and acetic acid, then oxidizing it with hydrogen peroxide in base. The reactions are:
 * Ce2(CO3)3 + 6 CH3COOH → 2 Ce(CH3COO)3 + 3 CO2↑ + 3 H2O
 * 2 Ce(CH3COO)3 + 3 H2O2 + 4 H2O → 2 Ce(OH)3(OOH) + 6 CH3COOH
 * CH3COOH + NaOH → CH3COONa + H2O
 * 2 Ce(OH)3(OOH) → 2 Ce(OH)4↓ + O2↑

The net equation is：
 * Ce2(CO3)3 + 6 CH3COOH + 3 H2O2 + 6 NaOH — 343 K → 2 Ce(OH)4 + 6 CH3COONa + O2↑ + 3 CO2↑ + 5 H2O

If using cerium(III) nitrate as ingredient, a similar reaction occurs:
 * 2 Ce(NO3)3 + 3 H2O2 + 6 NH3·H2O → 2 Ce(OH)3(OOH)↓ + 6 NH4NO3 + 2 H2O
 * Ce(OH)3(OOH) — Δ → 2 Ce(OH)4↓ + O2↑

It might also prepared by addition of sodium hydroxide or ammonium hydroxide to a Ce4+ solution, being obtained as a gelatinous precipitate described as CeO2·xH2O, (x = 0.5–2). Boiling an insoluble Ce4+ salt in NaOH gives granular Ce(OH)4.