Plutonium boride
The plutonium borides are a group of compounds that consist of the elements boron and plutonium . The 4 known plutonium borides to date are formed by direct reaction of both elements (boron in powder form) under a protective gas atmosphere at reduced pressure under certain temperature conditions.
Plutonium boride
Plutonium boride (PuB) is formed by reaction of the two elements at a temperature of 1200 ° C, with a boron content of 40 to 70%. It has an NaCl crystal structure (like other boron compounds TiB, ZrB and HfB). The bond length is 246 pm .
Another method is the reaction of a plutonium halide with magnesium diboride at low heat. This process is used to transfer more strongly radiating and therefore more dangerous radioactive substances into a less dangerous storage form.
Plutonium diboride
Plutonium diboride (PuB 2 ) is formed by the reaction of both elements at a temperature of 800 ° C, with a boron content of 60 to 65%. It has the structure of AlB 2 or UB 2 .
Plutonium tetraboride / plutonium hexaboride
From 1200 ° C, mixtures of plutonium tetraboride (PuB 4 ) and plutonium hexaboride (PuB 6 ) are formed, with a boron content of 70 to 85%; the amount of PuB 6 increases as the temperature rises. PuB 4 has a tetragonal UB 4 structure, PuB 6 the cubic CaB 6 structure ( isomorphic with ThB 6 ).
PuB 100
Perhaps the most notable plutonium boride is PuB 100 . Its existence demonstrates the importance of boride research on the subject of contamination, since less than 1% of an impurity causes its crystal structure to change.
Individual evidence
- ^ BJ McDonald, WI Stuart: "The crystal structures of some plutonium borides", in: Acta Cryst. , 1960 , 13 , pp. 447-448; doi : 10.1107 / S0365110X60001059 .
- ↑ a b Harry A. Eick: Plutonium Borides. In: Inorganic Chemistry . 4, 1965, pp. 1237-1239, doi : 10.1021 / ic50030a037 .
- ↑ Stefan Maier: A new process should make the storage of uranium and plutonium safer . In: Bild der Wissenschaft , April 11, 2001.