Radium carbonate
Radium carbonate Basic information
- Product Name:
- Radium carbonate
- Synonyms:
-
- RADIUMCARBONATE
- CAS:
- 7116-98-5
- MW:
- 0
- Mol File:
- 7116-98-5.mol
Radium carbonate Chemical Properties
- solubility
- insoluble in H2O
- color
- white orthorhombic crystals, crystalline
- Water Solubility
- insoluble H2O [HAW93]
Radium carbonate Usage And Synthesis
Description
Radium carbonate has the molecular formula of RaCO3 and the molecular weight of grams per mole. Most of the compounds of radium are more insoluble than the corresponding barium compounds and concentrate in the precipitate upon fractional precipitation of barium-radium mixtures. One notable exception is radium carbonate, which is more soluble than barium carbonate and, hence, concentrates in the soluble fraction (filtrate) when barium–radium carbonate mixtures are fractionally separated. Radium carbonate is soluble in dilute acids, and more soluble in concentrated ammonium carbonate solution than BaCO3.
Chemical Properties
amorphous, radioactive powder(s); pure material is white, but impurities impart yellow, orange, or pink color [HAW93]
Physical properties
Its volubility is 2.1×10-4 g/100 ml of water at 18°C. For this reason, precipitation as the sulfate is a common practice for the recovery of radium, particularly with the addition of bariumcarrier. Radium Carbonate is soluble in concentrated sulfuric acid, but precipitates upon dilution of the acid. It is converted to radium carbonate by fusion with sodium carbonate (a technique frequently used for the dissolution of radiferous barium sulfate because the resulting barium-radium carbonates are soluble in any dilute mineral acid).
Uses
The principal use of radium carbonate has been in medicine and to prepare other radium compounds.
Preparation
In general, RaCO3 is prepared in conjunction
with BaCO3 and then separated. Radium sulfate is
the most insoluble of the alkaline earth sulfates and probably
the most insoluble radium compound known.
Radium carbonate may also be prepared by precipitation
from neutral or weakly alkaline solutions of radium
salts with a solution of ammonium carbonate. Gram
quantities of radiumhave been recovered from a concentrated
solution of radium nitrate by precipitation as the
carbonate. The radium nitrate solution was adjusted to
pH 9.2-9.5 with concentrated ammonium hydroxide.
Carbon dioxide gas was bubbled into the solution until
the pH was just slightly above 7.0. To insure complete
precipitation of radium carbonate, ethyl alcohol
and some additional ammonium hydroxide solution
were added. The radium carbonate was filtered and
washed with 90% ethyl alcohol. It was first dried at
110°C to remove the alcohol and weighed as RaCO3.