Gadolinium sulfate

Many of the rare-earth compounds are strongly paramagnetic. Crystalline compounds of gadolinium, especially gadolinium sulfate octahydrate, Gd2(S04)3 8H20. arc used in the magnetic method of obtaining extremely low temperatures. 

The attainment of still lower temperatures, down to about 10" K, is achieved by making use of nuclear magnetic properties. The nuclear magnets are about 2000 times smaller than the magnet in a paramagnetic substance such as gadolinium sulfate, yet there is still a significant difference between the nuclear entropies even at temperatures as low as 10" K-... 

Giauque s best-known accomplishment is his invention and exploitation of cooling to very low temperatures by adiabatic demagnetization. In 1924, he learned of the unusual properties of gadolinium sulfate octahydrate at the temperature of liquid helium. In his Nobel Lecture, he said ... 

Gadolinium ethyl sulfate has extremely low noise characteristics and may find use in duplicating the performance of amplifiers, such as the maser. 

The relaxation of certain 13C nuclei in some uronic acids and derivatives is affected by Gd3+. For example, on addition of gadolinium nitrate to solutions of heparin or dermatan sulfate in D20, the C-l and C-6 signals of the uronic acid residues are selectively diminished. This property would be expected from a-L-idopyranosyluronic acid residues, as the C-l and C-6 signals of sodium a-D-idopyranuronate are similarly lessened in intensity, whereas those of the j8 anomer are... 

Gadolinium is produced from both its ores, monazite and bastnasite. After the initial steps of crushing and beneficiation, rare earths in the form of oxides are attacked by sulfuric or hydrochloric acid. Insoluble rare earth oxides are converted into soluble sulfates or chlorides. When produced from monazite sand, the mixture of sand and sulfuric acid is initially heated at 150°C in cast iron vessels. Exothermic reaction sustains the temperature at about 200 to 250°C. The reaction mixture is cooled and treated with cold water to dissolve rare earth sulfates. The solution is then treated with sodium pyrophosphate to precipitate thorium. Cerium is removed next. Treatment with caustic soda solution fohowed by air drying converts the metal to cerium(lV) hydroxide. Treatment with hydrochloric or nitric acid sol-... 

The hydrated sulfate is obtained by dissolving gadolinium(lll) oxide in... 

Miscellaneous compounds Cesium trihydrogen selenite Lithium trihydrogen selenite Potassium selenate Methyl ammonium alum (MASD) Ammonium cadmium sulfate Ammonium bisulfate Ammonium sulfate Ammonium nitrate Colemanite Cadmium pyroniobite Gadolinium molybdate... 

---