UPt3
Chemical compound
From Wikipedia, the free encyclopedia
UPt3 is an inorganic binary intermetallic crystalline compound of platinum and uranium.[1]
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| Names | |
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| Other names
Platinum--uranium (3/1) | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
PubChem CID |
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CompTox Dashboard (EPA) |
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| Properties | |
| UPt3 | |
| Molar mass | 823.3 g/mol[1] |
| Density | 19.3 g/cm3 |
| Melting point | 1700°C[2] |
| Structure | |
| see text | |
| 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).
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Production
It can be synthesised in the following ways:[3]
- as an intermetallic compound, by direct fusion of pure components according to stoichiometric calculations:
- by reduction of uranium dioxide with hydrogen in the presence of platinum:
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. Due to the large effective mass of the conduction electrons, UPt3 is classed as a Heavy fermion superconductor.[8][9]