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Samarium dissolves readily in dilute sulfuric acid to form solutions containing the yellow [22] to pale green Sm(III) ions, which exist as [Sm(OH 2) 9] 3+ complexes: [21] 2Sm (s) + 3H 2 SO 4 (aq) → 2Sm 3+ (aq) + 3SO 2− 4 (aq) + 3H 2 (g) Samarium is one of the few lanthanides with a relatively accessible +2 oxidation state, alongside Eu and ...
Some of the bastnäsites contain OH − instead of F − and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.
The DHCP (double hexagonal close-packed) form β-cerium is the equilibrium structure approximately from room temperature to −150 °C. The fcc form α-cerium is stable below about −150 °C; it has a density of 8.16 g/cm 3. Other solid phases occurring only at high pressures are shown on the phase diagram.
Samarium is one of the few lanthanides that form a monoxide, SmO. This lustrous golden-yellow compound was obtained by reducing Sm 2 O 3 with samarium metal at high temperature (1000 °C) and pressure above 50 kbar; lowering the pressure resulted in incomplete reaction. SmO has cubic rock-salt lattice structure.
Cerium(III) sulfate is one of the few salts whose solubility in water decreases with rising temperature. [12] Ceric ammonium nitrate. Due to ligand-to-metal charge transfer, aqueous cerium(IV) ions are orange-yellow. [13] Aqueous cerium(IV) is metastable in water [14] and is a strong oxidizing agent that oxidizes hydrochloric acid to give ...
Certain types of rare earth ores also contain radioactive thorium or uranium, which is often removed using acid. For this reason, development of the sector faces health and environmental ...
It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium, with traces of other rare earth metals totaling 95% lanthanides, plus 5% iron. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and
The cerium anomaly, in geochemistry, is the phenomenon whereby cerium (Ce) concentration is either depleted or enriched in a rock relative to the other rare-earth elements (REEs). [1] A Ce anomaly is said to be "negative" if Ce is depleted relative to the other REEs and is said to be "positive" if Ce is enriched relative to the other REEs. [1]