Conversion of protactinium monocarbide to the penta- and tetra-halides

Protactinium monocarbide has been prepared by carbothermic reduction of the pentaoxide. It reacts with iodine (400 °C), bromine (350 °C), and thionvl chloride (200 °C) in evacuated sealed vessels to vield the approoriate pentahaiibe. The tetraiodide, Pal4, is obtained by interaction of the monocarbide with either protactinium penta-iodide (600 °C) or mercury(II) iodide (500 °C)in vacuo. X-Ray powder-diffraction results and vibrational spectral data are reported for the halides.