Английская Википедия: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.[1][2] It has the chemical formula of Шаблон:Chem2.
Preparation
To obtain europium(III) chromate, an equimolar solution of europium(III) acetate and chromium(IV) oxide is dried in a vacuum at 70 °C and then heated to 400 °C in air.[3][4] 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 Шаблон:Cvt, 30 minutes at Шаблон:Cvt and then 1 hour at Шаблон:Cvt. A constant stream of oxygen is passed over the reaction mixture. An oxygen flow is used to stabilise the +5 oxidation state of chromium.[1]
Properties
Europium(III) chromate crystallizes tetragonally with space group I41/amd (No. 141) with lattice parameters a = 722.134(1) and c = 632.896(1) pm with four formula units per unit cell.[3]
The Néel temperature of europium(III) chromate is Шаблон:Cvt.[1] Above 700 °C, europium(III) chromate begins to decompose into europium chromite (Шаблон:Chem2).[2]
References
Шаблон:Europium compounds Шаблон:Chromium compounds
