Chemistry:Europium(III) chromate
| Names | |
|---|---|
| IUPAC name
Europium(III) chromate(V)
| |
Other names
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| Identifiers | |
| Properties | |
| EuCrO 4 | |
| Molar mass | 267.956 g·mol−1 |
| Density | 5.39 g/cm−3[1][2] |
| Melting point | 700 °C (1,292 °F; 973 K)[3] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
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.[4][3] It has the chemical formula of EuCrO
4.
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.[2][5] 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 433 K (160 °C; 320 °F), 30 minutes at 473 K (200 °C; 392 °F) and then 1 hour at 853 K (580 °C; 1,076 °F). A constant stream of oxygen is passed over the reaction mixture. An oxygen flow is used to stabilise the +5 oxidation state of chromium.[4]
- Eu(NO
3)
3 · 6H2O + Cr(NO
3)
3 · 9H2O → EuCrO
4 + 6 NO
2 + 15 H
2O + O
2
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.[2]
The Néel temperature of europium(III) chromate is 15.9 K (−257.2 °C; −431.0 °F).[4] Above 700 °C, europium(III) chromate begins to decompose into europium chromite (EuCrO
3).[3]
- 2 EuCrO
4 → 2 EuCrO
3 + O
2
References
- ↑ G. Buisson, E. F. Bertaut, J. Mareschal (1964), "Etude cristallographique des composes TCrO4 (T = terre rare ou Y)" (in German), Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences 259: pp. 411–413
- ↑ 2.0 2.1 2.2 Hidetaka Konno, Yoshitaka Aoki, Zoltán Klencsár, Attila Vértes, Makoto Wakeshima (2001-12-01). "Structure of EuCrO4 and Its Electronic and Magnetic Properties". Bulletin of the Chemical Society of Japan 74 (12): 2335–2341. doi:10.1246/bcsj.74.2335. ISSN 0009-2673. https://www.journal.csj.jp/doi/10.1246/bcsj.74.2335.
- ↑ 3.0 3.1 3.2 J. Thakur, R. Shukla, N. Raje, D. Ghonge, H. Bagla (2011-10-01). "Synthesis, Structural Characterization and Thermal Stability of Nanocrystalline Rare-Earth Chromates (RECrO4) and Rare-Earth Chromites (RECrO3)". Nanoscience and Nanotechnology Letters 3 (5): 648–654. doi:10.1166/nnl.2011.1233. https://www.ingentaconnect.com/content/asp/nnl/2011/00000003/00000005/art00008;jsessionid=1miu8i234ifxq.x-ic-live-01.
- ↑ 4.0 4.1 4.2 E Jiménez, J Isasi, R Sáez-Puche (2000-11-01). "Synthesis, structural characterization and magnetic properties of RCrO4 oxides, R=Nd, Sm, Eu and Lu". Journal of Alloys and Compounds 312 (1–2): 53–59. doi:10.1016/S0925-8388(00)01079-3. https://linkinghub.elsevier.com/retrieve/pii/S0925838800010793.
- ↑ Yoshitaka Aoki, Hidetaka Konno, Hiroto Tachikawa, Michio Inagaki (2000-05-01). "Characterization of LaCrO4 and NdCrO4 by XRD, Raman Spectroscopy, and ab Initio Molecular Orbital Calculations". Bulletin of the Chemical Society of Japan 73 (5): 1197–1203. doi:10.1246/bcsj.73.1197. ISSN 0009-2673. https://www.journal.csj.jp/doi/10.1246/bcsj.73.1197.
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