Radium phosphide would have the molecular
formula of Ra3P2 and the molecular weight of 740.0237 g/mol. It has no CAS number. It has never
been prepared but could be formed by reacting the metal
with red phosphorus at high temperature. The best way
is to sublime the P4 at 450°C in an inert gas stream and
react it with Ra metal at 600°C:
6Ra + 2P4 ? 2Ra3P4
It is expected to be a red–brown crystalline material
with a high melting point and to readily react with water
to form phosphine, PH3. There is absolutely no demand
for such a compound and it is likely that it will never be
prepared and its physical properties measured.
