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Europium(III) chromate

Europium(III) chromate is a chemical compound composed of europium, chromium and oxygen with europium in the +3 oxidation state, chromium in the +5 oxidation state and oxygen in the −2 oxidation state. It has the chemical formula of .

Properties

Europium(III) chromate crystallizes tetragonally with space group I4<sub>1</sub>/amd (No. 141) with lattice parameters a = 722.134(1) and c = 632.896(1) pm with four formula units per unit cell.

The Néel temperature of europium(III) chromate is . Above 700&nbsp;°C, europium(III) chromate begins to decompose into europium chromite ().

Preparation

To obtain europium(III) chromate, an equimolar solution of europium(III) acetate and chromium(IV) oxide is dried in a vacuum at 70&nbsp;°C and then heated to 400&nbsp;°C in air. Another way to obtain europium(III) chromate is by reacting stoichiometric amounts of europium(III) nitrate hexahydrate and chromium(III) nitrate nonahydrate for 30 minutes at , 30 minutes at and then 1 hour at . A constant stream of oxygen is passed over the reaction mixture. An oxygen flow is used to stabilise the +5 oxidation state of chromium.

References