Nickel partition coefficients

Mysen, B. O. (1978) Experimental determination of nickel partition coefficients... 

Michael PJ (1988) Partition coefficients for rare earth elements in mafic minerals of high silica rhyohtes the importance of accessory mineral inclusions. Geochim Cosmochim Acta 52 275-282 Mysen BO (1979) Nickel partitioning between olivine and silicate melt Henry s Law revisited. Am Mineral 64 1107-1114... 

Figure 2 Effect of oxygen fugacity on Z)(Ni), D(Ge), and D(P). Note that the partition coefficients for nickel decrease, for phosphorus increase and for germanium are constant as T increases parallel to a buffer. IW-1 refers to an oxygen fugacity 1 log/o unit below the IW oxygen buffer (sources Holzheid et aL, 1997 Schmitt etal., 1989 Hillgren, 1993 Newsom and Drake, 1983).

Figure 4 Metal/magnesiowUstite partition coefficients for nickel, cobalt, manganese, chromium, and vanadium at 9 GPa, and the effect of temperature (pressure 9 GPa). Partition coefficients are calculated relative to iron, according to the exchange equihhrium, M - - FeO = Fe + MO. Horizontal lines at right side of the diagram indicate the values of ATd that would he required for an equihhrium explanation for these hve elements in the terrestrial mantle (source Gessmann and Ruhie (1998) these authors favor a high-temperature scenario to attain these concentrations in the mantle).

Figure 6 Effect of silicate melt composition on metal/silicate partition coefficients for cobalt ( ), gallium (+), tungsten (o), and phosphorus ( ) (Jaeger and Drake, 2000 Pak and Fruehan, 1986). NBO/t is calculated according to Mysen (1991) and corresponds to basalt values of 1, komatiite —1.7, and peridotite —2.8. In general, high-valence elements such as tungsten and phosphorus are affected more strongly than lower valence elements such as cobalt (or nickel).

Figure 7 The effect of sulfur content of metallic liquid on the magnitude of the solid metal/liquid metal (SM/LM) partition coefficient. Note that copper and silver have an affinity for S-bearing liquid, whereas nickel, gallium, tungsten, osmium, and rhenium all prefer the solid metal. The connection to core formation is that the latter group of elements will have a lower metal/silicate partition coefficient if the metal is liquid and contains sulfur. Similar effects have been documented for carbon (Willis and Goldstein, 1982) (sources Chabot et al., 2003 Malvin et al., 1986 Jones and Drake, 1983 Liu and Reel, 2001 Fleet et al., 1999).

The behavior of some siderophile elements is controlled by the composition of the metal, and, in particular, the Fe/Ni ratio. Because the activity coefficient of a siderophile element, M, may be different in a nickel-rich metal than an iron-rich metal, an understanding of this effect is necessary before partition coefficients can be successfully applied to a natural system. A good example is tin, which has a low activity coefficient in iron-rich metal, and a high activity coefficient in nickel-rich metal (Figure 8 Capobianco et al., 1999). Metal composition can change as a function of/o, and this can then change the solubility in the silicate melt. In addition, the Fe/Ni ratio in metal is sometimes used to impose a specific/o on a system. These effects are linked and must be unraveled first in order to understand tin in planetary mantles (Righter and Drake, 2000). 

Figure 8 Variation of the activity coefficient (y) for Sn in nickel-rich metal (high /o ) versus iron-rich metal (low/o ). When the partition coefficients are corrected for this unusual behavior, anticipated valences of 2-h and 4-h become clear (source Capobianco et al. (1999), who also report activity coefficients for gallium and germanium).

Thibault Y. and Walter M. J. (1995) The influence of pressure and temperature on the metal/sihcate partition coefficients of nickel and cobalt in a model Cl chondrite and impheations for metal segregation in a deep magma ocean. Geochim. Cosmochim. Acta 59, 991 — 1002. 

Partition coefficients of nickel bis(dimethyldithiocarbamate) and bis(then-oyltrifluoroacetate) complexes between various organic solvents and aqueous perchlorate solution also show the effects of additional solvation, but this time probably at the metal atom, expanding the coordination number to six. " ... 

Magnetic transitions were shown to affect strongly the thermodynamic properties such as flie partition coefficient of nickel between ferrite and eementite or between eementite and austenite [1976Ko]. 

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