Arsenides of the Transition Metals: Viii. Some Binary and Ternary Group Viii Diarsenides and Their Magnetic and Electrical Properties

Abstract

The diarsenides of the cobalt and nickel families have been synthesized for magnetic susceptibility studies. The diffraction pattern of the low-temperature modificatioil of nickel diarsenide differs from that of the lnineral pararailln~elsbergite, although the space group is apparently idelltical and the unit cell dimensions comparable (orthorhombic Dig-Pbca; a = 5.770 f 0.007, b = 5.838 f 0.006, c = 11.419 f 0.008 A). These binary diarsenides exhibit temperature dependent diamagnetic or weakly paramagnetic behavior. Temperature dependence of electrical resistivity indicates that PdAs? is metallic while PtAs? is a semiconductor with a n energy gap of -0.17 eV.Substitutional solid solution limits have been determined for various Group VIII transition metal atoms in the pyrite phases PdAs? and PtAs?, and in the skutterudites RhAss and IrAs3. There is no substitution by Ru or 0 s in PdAse, by Ni or P t in PdAs?, by Ru or Ag in RhAs3, or by 0 s in IrAs3. Very limited substitutions were observed for Rh and Ag in PdAs?, Pd in I'tAs?, Pd in Rh.4~3, and I' t in IrAss. The limit of Co substitution in PdAs? is 8.2 f 0.3atoln 7 0 , and of Ni in I'dAs?, 56.7 f 0.3 atom %.111 the Co,Pdl-,As? system, a temperature-dependent paramagnetic colltribution corresponding to approximately one uncompensated spin per cobalt ion has been attributed to the t5?, loiv-spin configuration of the Co ion in the pyrite structure. In the Ni,Pdl-,As2 system, the temperature-independent paramagnetic contribution by the nickel ions is not colnpletely ~inderstood.

The effects of post-cumulus alteration on the distribution of chalcophile elements in magmatic sulfide deposits and implications for the formation of low-S-high-PGE zones: The Luanga deposit, Carajás Mineral Province, Brazil

“…However, TABSþ form PGM that are stable at different conditions. For example, As and Sb are more frequently associated with Pt, and form PGM that are stable at higher temperatures (Bennett & Heyding 1966, Dare et al 2010a, Helmy et al 2013, Bai et al 2017. In contrast, Te and Bi are frequently combined with Pd and form PGM that have lower melting temperatures (Cabri & Laflamme 1976, Hoffman & MacLean 1976, Helmy et al 2007, Tomkins et al 2007, Dare et al 2014, Duran et al 2017).…”

MINERALOGY OF RARE OCCURRENCES OF PRECIOUS-METAL-ENRICHED MASSIVE SULFIDE IN THE VOISEY'S BAY Ni-Cu-Co OVOID DEPOSIT, LABRADOR, CANADA

“…On the basis of characteristics of sperrylite from the Southeast Extension dyke, it is possible that sperrylite in the Ovoid samples may have been strongly associated with chalcopyrite before EPD processing. On the other hand, the large sizes of sperrylite grains and their experimentally derived melting temperatures would suggest that sperrylite crystallized early from a parental sulfide melt, at high temperatures (>1400 o C, Hansen & Anderko 1958, Bennett & Heyding 1966, prior to iss crystallization. Detailed investigations of crystallization processes of the sulfide and PGM that relate the mineralization of the dyke of the Southeast Extension Zone to the Ovoid is the subject of our ongoing studies.…”