Cerium(IV) hydroxide
# 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:

    $Ce_2(CO_3)_3$ + 6 $CH_3COOH$ → 2 $Ce(CH_3COO)_3$ + 3 $CO_2↑$ + 3 $H_2O$
    2 $Ce(CH_3COO)_3$ + 3 $H_2O_2$ + 4 $H_2O$ → 2 $Ce(OH)_3(OOH)$ + 6 $CH_3COOH$
    $CH_3COOH$ + NaOH → $CH_3COONa$ + $H_2O$
    2 $Ce(OH)_3(OOH)$ → 2 $Ce(OH)_4↓$ + $O_2↑$

The net equation is：

    $Ce_2(CO_3)_3$ + 6 $CH_3COOH$ + 3 $H_2O_2$ + 6 NaOH $—^{343K}→$ 2 $Ce(OH)_4$ + 6 $CH_3COONa$ + $O_2↑$ + 3 $CO_2↑$ + 5 $H_2O$

If using cerium(III) nitrate as ingredient, a similar reaction occurs:

    2 $Ce(NO_3)_3$ + 3 $H_2O_2$ + 6 $NH_3·H_2O$ → 2 $Ce(OH)_3(OOH)↓$ + 6 $NH_4NO_3$ + 2 $H_2O$
    $Ce(OH)_3(OOH)$ $—^Δ→$ 2 $Ce(OH)_4↓$ + $O_2↑$

It might also prepared by addition of sodium hydroxide or ammonium hydroxide to a $Ce^{4+}$ solution, being obtained as a gelatinous precipitate described as $CeO_2·xH_2O,$ (x = 0.5–2). Boiling an insoluble $Ce^{4+}$ salt in NaOH gives granular $Ce(OH)_4.$

