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]

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:

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

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]}