FeO-SiO2
The new end-member in this subsystem is goethite, and its enthalpy has been derived from the high pressure experiments of Voigt & Will (1981) on the reaction 2gth = hem + H2O.
The data for fayalite, quartz, magnetite, hematite and iron are now in excellent agreement with the experiments of Bohlen et al. (1980), Chou (1978), Myers & Eugster (1983), Hewitt (1978), and especially O'Neill (1987, 1988). Siderite enthalpy is now fitted to the experiments of Koziol & Newton (1993) on the reaction sid + hem = mt + CO2.
Deerite data are fitted to the experiments of Lattard & LeBreton (1994) for the reactions 2 deer = 9fs + 6mt + 6q + 10H2O and deer + Ni = 6fs + 2mt + NiO + 5H2O. Grunerite data are derived from the experiments of Lattard & Evans (1992) on the reactions 2grun = 7fs + 2q + 2H2O and 2grun = 7fa + 9q + 2H2O.
215) fs = fa + q (Bohlen et al., 1980)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 - 10.7 10.3 700 -0.46 -0.35 10.32 0.28 3 (-0.44 <-> -0.27)
0 - 11.2 10.8 750 -0.44 -0.32 10.92 0.29 cH = -0.35 (sd 0.03)
0 - 11.7 11.3 800 -0.41 -0.29 11.52 0.30 within bracket
0 - 12.2 11.8 850 -0.37 -0.25 12.14 0.30 uH = 0.07, d/s = 0.2, h = 0.99
0 - 12.9 12.4 900 -0.39 -0.23 12.79 0.31
0 - 13.5 13.1 950 -0.37 -0.25 13.44 0.32
0 - 14.3 13.9 1000 -0.43 -0.30 14.06 0.33
0 - 15.0 14.6 1050 -0.46 -0.34 14.65 0.34
216) 4mt + O2 = 6hem (Myers & Eugster, 1983)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
10.82 - 0.0 1053 1043 -490.23 -483.67 5 1058 6 3 (-490.87 <-> -486.05)
9.59 - 0.0 1083 1073 -487.71 -481.21 12 1095 6 cH = -492.19 (sd 1.19) 2
8.77 - 0.0 1113 1103 -489.21 -482.71 8 1121 6 too low but OK
8.06 - 0.0 1142 1132 -491.22 -484.73 3 1145 6 uH = 1.72, d/s = -0.5, h = 0.32
7.21 - 0.0 1172 1162 -491.69 -485.21 1 1173 6
6.48 - 0.0 1201 1191 -492.68 -486.22 1200 8
5.74 - 0.0 1228 1218 -492.72 -486.25 1226 8
5.08 - 0.0 1262 1252 -495.64 -489.14 1251 8
4.79 - 0.0 1274 1264 -495.81 -489.30 1263 8
217) 4mt + O2 = 6hem (Chou, 1978)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
36.15 - 2.0 605 595 -505.21 -495.03 -11 584 4 3 (-498.42 <-> -491.61)
31.64 - 2.0 655 645 -500.91 -491.01 640 4 cH = -492.19 (sd 1.19)
27.38 - 2.0 705 695 -494.12 -488.59 701 4 within bracket
24.96 - 2.0 755 745 -499.22 -489.62 741 4 uH = 2.82, d/s = -0.2, h = 0.36
22.29 - 2.0 805 795 -500.06 -490.43 788 6
218) 3fa + O2 = 3q + 2mt (Chou, 1978)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
45.08 - 2.0 605 595 -528.65 -519.25 1 606 4 3 (-528.78 <-> -521.82)
41.65 - 2.0 655 645 -529.09 -519.80 655 4 cH = -529.08 (sd 0.95) 2
38.59 - 2.0 705 695 -529.60 -520.34 704 4 too low but OK
36.01 - 2.0 755 745 -531.69 -522.41 749 4 uH = 2.49, d/s = 1.3, h = 0.06
33.41 - 2.0 805 795 -531.38 -522.09 800 4
219) 3fa + O2 = 3q + 2mt (Myers & Eugster, 1983)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
41.85 - 0.0 666 656 -532.05 -520.90 660 4 1 (-528.55 <-> -521.52)
38.55 - 0.0 716 706 -530.37 -519.20 713 4 cH = -529.08 (sd 0.95) 2
38.09 - 0.0 721 711 -529.05 -517.84 721 4 too low but OK
36.63 - 0.0 750 740 -530.44 -519.22 747 4 uH = 2.33, d/s = 1.7, h = 0.06
35.77 - 0.0 770 760 -532.32 -521.03 763 4
21.81 - 0.0 1123 1113 -531.77 -519.33 1115 6
21.33 - 0.0 1138 1128 -531.21 -518.74 1132 6
220) 3fa + O2 = 3q + 2mt (Hewitt, 1978)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
42.64 - 1.0 657 647 -535.68 -526.80 644 4 1 (-532.81 <-> -526.95)
39.08 - 1.0 709 699 -533.42 -525.98 700 4 cH = -529.08 (sd 0.95)
36.26 - 1.0 757 747 -532.69 -527.07 749 4 within bracket
31.25 - 2.0 857 847 -533.84 -526.20 846 4 uH = 2.31, d/s = 1.2, h = 0.25
221) 3fa + O2 = 3q + 2mt (O'Neill, 1987)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
37.98 - 0.0 732 722 -533.37 -526.61 723 4 3 (-531.99 <-> -526.76)
32.77 - 0.0 832 822 -533.17 -526.66 823 4 cH = -529.08 (sd 0.95)
28.43 - 0.0 932 922 -532.94 -526.59 922 4 within bracket
24.74 - 0.0 1032 1022 -532.51 -526.26 1023 6 uH = 1.92, d/s = 1.4, h = 0.42
21.56 - 0.0 1132 1122 -531.88 -525.69 1124 6
222) q + 2iron + O2 = fa (O'Neill, 1987)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
50.76 - 0.0 732 722 -570.72 -563.05 726 2 1 (-569.60 <-> -563.36)
44.56 - 0.0 832 822 -570.58 -563.22 826 2 cH = -567.34 (sd 0.68)
39.38 - 0.0 932 922 -570.28 -563.22 926 2 within bracket
35.00 - 0.0 1032 1022 -569.95 -563.02 1026 4 uH = 2.29, d/s = 1.4, h = 0.16
31.26 - 0.0 1132 1122 -569.74 -562.92 1126 4
223) 3iron + 2O2 = mt (O'Neill, 1988)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
138.74 - 0.0 482 472 -1123.92-1106.36 476 2 1 (-1123.82 <-> -1107.05)
127.80 - 0.0 532 522 -1123.75-1106.90 526 2 cH = -1115.55 (sd 0.98)
121.32 - 0.0 565 555 -1123.62-1107.24 559 2 within bracket
uH = 6.54, d/s = 1.3, h = 0.03
224) 2gth = hem + H2O (Voigt & Will, 1981)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0 10.0 180 200 55.63 56.45 184 4 3 (55.46 <-> 56.07)
0 0 20.0 250 280 55.00 56.23 269 4 cH = 55.77 (sd 0.22)
0 0 30.0 300 350 54.55 56.53 331 6 within bracket
0 0 40.0 350 400 54.74 56.43 379 10 uH = 0.22, d/s = 0.7, h = 1.00
0 0 50.0 400 420 55.20 55.95 415 12
225) sid + hem = mt + CO2 (Koziol, pers com 1994)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 1 6.0 510 520 77.25 78.30 519 6 3 (77.45 <-> 78.94)
0 1 8.0 550 570 77.10 79.23 560 6 cH = 78.17 (sd 0.36)
0 1 9.0 570 590 77.23 79.41 579 6 within bracket
0 1 10.0 590 600 77.51 78.60 596 6 uH = 0.63, d/s = 0.1, h = 0.90
0 1 11.0 600 620 76.78 78.92 613 6
0 1 12.0 630 640 78.23 79.29 -1 629 6
226) 2grun = 7fs + 2q + 2H2O (Lattard & Evans, 1992)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0 16.0 599 200.11 604 20 6 (199.59 <-> 201.42)
0 0 12.0 637 200.57 1 638 18 cH = 200.69 (sd 1.06)
0 0 14.0 620 200.45 622 20 within bracket
0 0 20.0 563 588 200.58 203.21 564 22 uH = 0.66, d/s = -0.0, h = 0.70
227) 2grun = 7fa + 9q + 2H2O (Lattard & Evans, 1992)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0 2.0 549 573 196.51 200.76 559 12 1 (196.94 <-> 200.33)
cH = 198.22 (sd 1.07)
within bracket
uH = 0.89, d/s = 2.4, h = 0.31
228) 2deer = 9fs + 6mt + 6q + 10H2O (Lattard & Le Breton, 1994)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0 20.0 600 626 609.47 621.94 625 16 2 (616.47 <-> 626.43)
0 0 27.0 710 740 620.96 634.50 711 18 cH = 621.42 (sd 3.62)
within bracket
uH = 3.57, d/s = 0.1, h = 0.65
229) deer + Ni = 6fs + 2mt + NiO + 5H2O (Lattard & Le Breton, 1994)
ln_K x(CO2) P(kbar) T(C) H(low) H(high) miss calc 2sd summary
0 0 21.5 570 328.60 604 18 2 (334.32 <-> 338.31)
0 0 20.0 600 338.33 591 16 cH = 336.34 (sd 1.84)
0 0 27.0 640 670 334.29 340.83 649 18 within bracket
uH = 1.43, d/s = 1.4, h = 0.37
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