TY - JOUR
T1 - A thermochemical study of the distribution of cobalt and nickel between diopsidic pyroxene and melt
AU - Wright, David P.
AU - Navrotsky, Alexandra
N1 - Funding Information:
Acknowledgements-Thwis orkw ass upportedb y NSF Grants EAR 8022223 and 8405218 and by DOE Contract DEAC0280ER10768W. e thankA . Yatesf or helpw ith XRF, J. Clark for help with EPMA, J. Stuarta nd C. Capobianco for assistancwe ith the computera nalyseas nd R. Hervigf or helpw henevenr eededT. he tirsta uthora lsot hankst hes econd for all thoset hingsw hich aret oo numerousto list here.T his work formedt he basisf or DPw’s seniorh onorst hesis.
PY - 1985/11
Y1 - 1985/11
N2 - Glasses and crystals of compositions MgCaSi2O6, CoCaSi2O6 and NiCaSi2O6 were studied by high temperature solution calorimetry, x-ray diffraction, and pycnometry. These data were combined with trace element distribution data to obtain values for ΔAG0, ΔH0, ΔS0, and ΔV0 for M-Mg exchange reactions. Enthalpies of vitrification increase in the order Co, Mg, Ni as do volumes of vitrification and apparent melting points. The mixing of Co and Mg, Ni and Mg, and Co and Ni is almost ideal in crystals and glasses, with small negative heats of mixing and small volume changes. The exchange reactions MgCaSi2O6 (xl) + MCaSi2O6 (liq) = MgCaSi2O6 (liq) + MCaSi2O6 (xl) are exothermic for Ni and endothermic for Co. The volumes and entropies of the exchange reaction are small.
AB - Glasses and crystals of compositions MgCaSi2O6, CoCaSi2O6 and NiCaSi2O6 were studied by high temperature solution calorimetry, x-ray diffraction, and pycnometry. These data were combined with trace element distribution data to obtain values for ΔAG0, ΔH0, ΔS0, and ΔV0 for M-Mg exchange reactions. Enthalpies of vitrification increase in the order Co, Mg, Ni as do volumes of vitrification and apparent melting points. The mixing of Co and Mg, Ni and Mg, and Co and Ni is almost ideal in crystals and glasses, with small negative heats of mixing and small volume changes. The exchange reactions MgCaSi2O6 (xl) + MCaSi2O6 (liq) = MgCaSi2O6 (liq) + MCaSi2O6 (xl) are exothermic for Ni and endothermic for Co. The volumes and entropies of the exchange reaction are small.
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U2 - 10.1016/0016-7037(85)90238-8
DO - 10.1016/0016-7037(85)90238-8
M3 - Article
AN - SCOPUS:0022183654
VL - 49
SP - 2385
EP - 2393
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
IS - 11
ER -