RADIUMNITRATE

Description

Radium nitrate had the molecular formula of Ra(NO3)2 and the molecular weight of 350.0343 g/mol. It can be prepared by a number of methods. The reaction between nitric acid and radium metal is one way and reaction with Ra RaO or RaCO3 is another. Radium hydroxide and ammonium nitrate also form the product but ammonia is released as a by-product:
2HNO3 + Ra ? Ra(NO3)2 +H2
2HNO3 + RaO ? Ra(NO3)2 +H2O
Ra(OH)2 + 2NH4NO3 ? Ra(NO3)2 + 2NH3 + 2H2O
Radium nitrate can also be prepared by the reaction of radium carbonate with nitric acid. The product is soluble but can be isolated by evaporation of the solution at low temperature.

Preparation

Radium nitrate can also be prepared by the reaction of radium carbonate with nitric acid. The product is soluble but can be isolated by evaporation of the solution at low temperature. It occurs as the anhydrate, like barium nitrate, but is slightly more soluble at 12.1 g/100 ml at 20°C. Its CAS number is 10213-12-4. When heated, Ra(NO3)2 decomposes at about 280°C to form RaO. A number of other oxides have been proposed but this decomposition mechanism has not been thoroughly studied. Like the barium analog, the decomposition is probably complex and may involve the peroxides as well. Temperatures above 820°C are probably required to obtain an oxide. Whether the nitrite is involved during the decomposition is not known.
Little interest has been shown for this compound in industry. The main academic and scientific interest in radium nitrate has been the fact that, since it is soluble (and the ²²⁶Ra isotope has a 1600 year half-life), the presence of radium nitrate, even in pico-gram quantities (10^-12 g/ml) of ingested water is sufficient to cause health problems in the human body because it accumulates in the bones while continuing to emit energetic g-rays.