The Hg-Pd-Te system: phase relations involving temagamite and a new ternary phase

[摘要] Phase relations in the Hg–Pd–Te system were studied at 350°C using the silica glass tube method. The following binary phases were confirmed to be stable at 350°C: PdHg (potarite), HgTe (coloradoite), Pd13Te3, Pd20Te7 (keithconnite),Pd7Te3, Pd9Te4 (telluropalladinite), Pd3Te2, PdTe (kotulskite), and PdTe2 (merenskyite). Kotulskite (PdTe) dissolves upto 8 at. % Hg at 350°C. Other palladium tellurides do not dissolve Hg. Two ternary phases were proved to be stable inthe system at 350 °C: Pd3HgTe3 (temagamite) and a new phase Pd4HgTe3. The Pd4HgTe3 phase is orthorhombic, Pnmaspace group with unit-cell parameters a = 13.1520(2), b = 11.6879(2), c = 4.25758(5) Å, V = 654.480(5) Å3 and Z = 4.The Pd4HgTe3 phase can be viewed as a ternary ordered variant of the Hg-bearing kotulskite. Synthetic temagamite formsstable assemblages with several phases representing minerals merenskyite and coloradoite, coloradoite and potarite,merenskyite and kotulskite, phase Pd4HgTe3 and kotulskite s.s., and phase Pd4HgTe3 and potarite. The occurrence oftemagamite and its associations indicate the formation of mineralization below 570°C. The new phase Pd4HgTe3 formsstable associations with synthetic analogs of temagamite and potarite, potarite and telluropalladinite, telluropalladiniteand kotulskite s.s., temagamite and kotulskite s.s. The phase Pd4HgTe3 can be expected to be found in such associationsunder natural conditions.

[学科分类] 自动化工程

[关键词] Hg–Pd–Te system;Pd–Hg tellurides;phase relations;temagamite;platinum-group minerals;new ternary phase