UPt3

Uranium platinum

Names
Other names Platinum--uranium (3/1)
Identifiers
CAS Number	12311-92-1
3D model (JSmol)	Interactive image
PubChem CID	71354824
CompTox Dashboard (EPA)	DTXSID90779273
InChI InChI=1S/3Pt.U Key: YYBWTXHBZRZQRM-UHFFFAOYSA-N
SMILES [Pt].[Pt].[Pt].[U]
Properties
Chemical formula	UPt3
Molar mass	823.3 g/mol [1]
Density	19.3 g/cm3
Melting point	1700°C [2]
Structure
Crystal structure	see text
Space group	P63/mmc
Thermochemistry
Std molar entropy (S⦵298)	−111 J·mol−1·K−1 [3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

UPt₃ is an inorganic binary intermetallic crystalline compound of platinum and uranium. ^[1]

Production

It can be synthesised in the following ways: ^[3]

• as an intermetallic compound, by direct fusion of pure components according to stoichiometric calculations:

${\displaystyle {\mathsf {3Pt+U\ {\xrightarrow {1700^{o}C}}\ UPt_{3}}}}$

• by reduction of uranium dioxide with hydrogen in the presence of platinum:

${\displaystyle {\mathsf {UO_{2}+2H_{2}+3Pt\ {\xrightarrow {1700^{o}C}}\ UPt_{3}+2H_{2}O}}}$

Physical properties

UPt₃ forms crystals of hexagonal symmetry (some studies hypothesize a trigonal structure instead ^[4] ), space group P6₃/mmc, ^[5] cell parameters a = 0.5766 nm and c = 0.4898 nm (c should be understood as distance from planes), with a structure similar to nisnite (Ni₃Sn) and MgCd₃. ^{[6] [7]}

The compound congruently melts at 1700 °C. ^[2] The enthalpy of formation of the compound is -111 kJ/mol. ^[3]

At temperatures below 1 K it becomes superconducting, thought to be due to the presence of heavy fermions (the uranium atoms). ^{[8] [9]}

References

1. PubChem. "Platinum--uranium (3/1)". pubchem.ncbi.nlm.nih.gov. Retrieved 2022-10-18.
2. Lyakishev, N.P., ed. (2001). Диаграммы состояния двойных металлических систем[State diagrams of binary metal systems]. Mechanical Engineering (in Russian). Vol. 3, book 3. Moscow. p. 448. ISBN   5-217-02932-3.
3. Kleykamp, Heiko (1991). "Thermodynamics of the uranium-platinum metals systems" (PDF). Pure and Applied Chemistry. Vol. 63, no. 10. pp. 1401–1408. doi:10.1351/pac199163101401. Archived from the original on 14 February 2015. Retrieved 2022-10-17.
4. Walko, D. A.; Hong, J.-I.; Chandrasekhar Rao, T. V. (2001-01-16). "Crystal structure assignment for the heavy-fermion superconductor UPt₃". Physical Review B. Vol. 63, no. 5. p. 054522. doi:10.1103/PhysRevB.63.054522 . Retrieved 2022-10-18.
5. Sumita, Shuntaro; Yanase, Youichi (2018-04-13). "Unconventional superconducting gap structure protected by space group symmetry". Physical Review B. 97 (13): 134512. arXiv: 1801.03293 . Bibcode:2018PhRvB..97m4512S. doi:10.1103/PhysRevB.97.134512. S2CID   119100443.
6. Predel (1998). "Pt-U (Platinum-Uranium)". Ni-Np – Pt-Zr. Landolt-Börnstein - Group IV Physical Chemistry. Springer-Verlag. pp. 1–2. doi:10.1007/10542753_2536. ISBN   3-540-61712-4.
7. Ross, B. A. S.; Peterson, D. E. (1990-06-01). "The Pt-U (Platinum-Uranium) system". Bulletin of Alloy Phase Diagrams. Vol. 11, no. 3. pp. 240–243. doi:10.1007/BF03029291 . Retrieved 2022-10-09.
8. Gurtovoy, К. G.; Levitin, R. Z. (October 1987). "Магнетизм актинидов и их соединений" [Magnetism of actinides and their compounds](PDF). Успехи физических наук (Advances in the Physical Sciences). Vol. 153, no. 2. Retrieved 2022-10-09.
9. Mineev, V. P. (1994). "Superconductivity in UPt3". Annales de Physique. Vol. 19, no. 4. pp. 367–384. doi:10.1051/anphys:01994001904036700 . Retrieved 2022-10-09.