The carbothermic reduction of protactinium pentoxide and first results on protactinium carbide

Critical review of carbon monoxide pressure measurements in the uranium–carbon–oxygen ternary system

“…Though this work deals with the carbothermic reduction of protactinium oxide, some additional measurements were also performed on the U-C-O system [21]. A pelletized mixture of U 3 O 8 and graphite was used as starting material.…”

“…The critical analysis of literature data is performed on mass-spectrometric measurements [18] and on manometric pressure determinations either by applying the thermomolecular effect correction for data measured in the molecular flow regime or using our formula (8) for those performed in the transition flow regime [2,3,5,[19][20][21]. For all the studies considered (see Tables 2 and 3 As a general rule, the gas phase composition was either analysed directly by mass spectrometry [18] or following the mass spectrometric analysis of gas.…”

Protactinium

“…The unit cell constant of a-PaH 3 is (4.150 AE 0.002) Å for the product obtained at 100 and 200 C and (4.154 AE 0.002) Å at 300 C. Subsequently, Brown (1982) prepared aand b-PaH 3 at 250 and 400 C, respectively. Table 4.6 Preparation and structure of protactinium-noble-metal alloy phases (Erdmann, 1971;Erdmann andKeller, 1971, 1973 Lorenz et al (1969) prepared PaC by reduction of Pa 2 O 5 with graphite at reduced pressure and temperatures above 1200 C. The product obtained at 1950 C was face-centered cubic ( fcc) (NaCl type) with a ¼ (5.0608 AE 0.0002) Å . At 2200 C, some additional weak lines, attributable to PaC 2 , were observed; this structure was body-centered tetragonal with a ¼ (3.61 AE 0.01) Å and c ¼ (6.11 AE 0.01) Å .…”