The synthesis and characterization of crystalline phosphates of thorium, uranium and neptunium

Chemistry of tetravalent actinide phosphates—Part II

“…The XRD pattern of the ''uranyl(IV)'' diphosphate (UO) 2 P 2 O 7 was published for the first time by Dunn [7]. Then, other authors [22][23][24] mentioned the same formula. Single crystals of U 2 O(PO 4 ) 2 were obtained by chemical vapor transport from 800 to 900 1C from reaction of U(PO 3 ) 4 with UP 2 and iodine in an evacuated, sealed silica tube in a two-zone furnace [25].…”

“…The frequencies of the Th-O-Th bond in Th 2 O(PO 4 ) 2 was interpreted in the same way [13]. Moreover, in the Raman spectrum of the (NpO) 2 P 2 O 7 [23], the weak band at about 790 cm À1 may be assigned to the Np-O-Np, which leads to the re-definition of its formula. Mal'shikov and Bondar' [29] synthesized a compound ''(HfO) 2 P 2 O 7 '' and suggested this formula basing on a weak band at 747 cm À1 in the IR spectrum.…”

Phase study in Sr–Th–P–O system: Structural and thermal investigations of quaternary compounds

“…During the present work, attempts were made to synthesize Th 3 P 2 O 11 and Th 3 P 4 O 16 by solid state route by heating the reactants in required proportions at 1223 K, but both the reaction products were identified as a mixture of TPD and ThO 2 and were not included in the phase diagram study. The existence of Th 3 P 4 O 16 , synthesized by Bamberger et al [31] was doubted by Brandel et al [20], stating that either the phase is wrong or does not exist. A well established and most stable phase in ThO 2 -P 2 O 5 system, Th 4 (PO 4 ) 4 (P 2 O 7 ), is synthesized either by solid state or by solution route by heating the precursors at 1523 K [16,19].…”

“…In SrO-ThO 2 system, SrThO 3 is the only compound reported so far and its thermal expansion was investigated using dilatometry [30]. The synthesis and characterization of various phosphates of thorium are reported by Bamberger et al [31]. Sarawadekar and Kulkarni [32] have studied the structural and thermal properties of various alkaline earth metal ortho-phosphates using XRD, TG/DTA and IR techniques.…”

Facile Routes to ThIV, UIV, and NpIV Phosphites and Phosphates

“…[4][5][6][7][8][9][10] However, few neptunium phosphates have been prepared as pure phases. [11][12][13][14][15][16] More recently, actinide phosphonates have been explored owing to their possible uses in these nuclear processes.…”