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Oxidizing Rhodium with Sulfuric Acid: The Sulfates Rh 2 (SO 4 ) 3 and Rh 2 (SO 4 ) 3 ·2H 2 O
Author(s) -
Schwarzer Stefan,
Betke Annika,
Logemann Christian,
Wickleder Mathias S.
Publication year - 2017
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201601247
Subject(s) - rhodium , chemistry , orthorhombic crystal system , sulfuric acid , thermal decomposition , oxidizing agent , decomposition , infrared spectroscopy , inorganic chemistry , crystallography , analytical chemistry (journal) , crystal structure , nuclear chemistry , catalysis , organic chemistry
The reaction of elemental rhodium and concentrated sulfuric acid (97 %) at 400 °C leads to red plate‐shaped single crystals of Rh 2 (SO 4 ) 3 [trigonal, R 3 , Z = 6, a = 806.8(1) pm, c = 2204.8(4) pm, V = 1242.8(4) × 10 6 pm 3 ]. The same reaction carried out at a temperature of 475 °C leads to orange crystals of Rh 2 (SO 4 ) 3 · 2H 2 O [orthorhombic, Pnma, Z = 4, a = 920.46(2) pm, b = 1244.47(3) pm, c = 833.37(2) pm, V = 954.61(4) × 10 6 pm 3 ]. Thermal analysis and X‐ray powder diffraction measurements were performed to investigate the decomposition and resulting residues of the compounds. For both compounds the decomposition occurs through two steps and is finished at around 1000 °C at the stage of elemental rhodium. Additionally both sulfates were characterized by means of IR spectroscopy.