Table S1 (online resource 1) (a) Lattice parameters of goethite, ε-FeO(OH) and its dehydration

products as a function of P and T.

No. T [°C] P [GPa] V [ų] a [Å] b [Å] c [Å] Run R05 Goethite 1 25 0.0001 138.6±0.1 4.607±0.002 9.956±0.004 3.023±0.001 2 25 0.67 137.5±0.1 4.590±0.003 9.933±0.004 3.017±0.001 3 25 1.68 136.7±0.3 4.573±0.005 9.923±0.010 3.012±0.004 4 25 2.18 136.3±0.3 4.566±0.008 9.937±0.012 3.003±0.003 5 25 3.63 134.1±0.2 4.546±0.006 9.893±0.005 2.982±0.002 6 25 5.40 132.2±0.2 4.524±0.005 9.865±0.007 2.961±0.002 7 100 5.72 132.3±0.3 4.522±0.009 9.848±0.008 2.969±0.002 8 150 5.82 132.7±0.2 4.529±0.006 9.860±0.007 2.972±0.002 9 200 5.78 132.9±0.2 4.519±0.006 9.875±0.008 2.979±0.002 10 250 5.64 133.2±0.1 4.517±0.003 9.873±0.003 2.987±0.001 11 300 5.41 133.6±0.2 4.517±0.006 9.879±0.007 2.994±0.002 11b 300 5.41 133.6±0.3 4.529±0.007 9.886±0.008 2.985±0.002 12 350 5.40 134.2±0.2 4.525±0.005 9.873±0.006 3.003±0.002 13 400 5.50 134.1±0.1 4.519±0.002 9.881±0.003 3.003±0.001 Run R05 Magnetite 14 450 5.54 581.8±0.4 8.348±0.003 14b 450 5.54 583.3±0.3 8.355±0.002 15 500 5.54* 584.7±0.1 8.362±0.001 Run R22 Goethite 1 25 0.02 138.8±0.2 4.612±0.003 9.959±0.006 3.023±0.003 2 25 1.58 137.4±0.1 4.585±0.002 9.943±0.002 3.013±0.001 3 25 2.99 135.4±0.1 4.560±0.003 9.908±0.004 2.998±0.002 4 25 4.23 134.7±0.2 4.544±0.003 9.909±0.005 2.991±0.002 5 25 5.43 132.7±0.1 4.521±0.003 9.871±0.004 2.973±0.002 6 25 6.50 132.0±0.2 4.516±0.004 9.868±0.006 2.963±0.003 7 50 6.80 131.2±0.1 4.499±0.003 9.840±0.004 2.964±0.002 8 100 6.70 131.8±0.3 4.500±0.006 9.846±0.009 2.974±0.005 9 150 6.72 132.0±0.2 4.490±0.005 9.863±0.007 2.980±0.004 10 200 6.68 132.3±0.1 4.493±0.002 9.859±0.003 2.987±0.002 11 250 6.43 132.6±0.1 4.493±0.002 9.863±0.003 2.993±0.002 12 300 6.50 133.2±0.1 4.502±0.001 9.871±0.002 2.997±0.001 13 350 6.28 133.9±0.2 4.497±0.004 9.898±0.005 3.009±0.002 Run R22 Magnetite 14 400 6.23 580.9±0.2 8.344±0.002 15 450 6.21 583.1±0.1 8.355±0.001 16 500 5.99 586.8±0.2 8.372±0.002 Run R22 Wüstite 16 500 5.99 78.6±0.0 4.283±0.000 Run R22 ε-FeO(OH) 13 350 6.28 64.1±0.1 4.914±0.004 4.368±0.002 2.985±0.002 13b 350 6.28 64.2±0.1 4.915±0.005 4.370±0.003 2.990±0.002 14 400 6.23 64.3±0.1 4.914±0.006 4.381±0.003 2.986±0.002 Run R24 Goethite 1 25 0.03 138.6±0.1 4.608±0.002 9.952±0.005 3.022±0.002 2 25 2.51 136.2±0.3 4.568±0.006 9.926±0.008 3.003±0.005 4 25 5.10 133.0±0.1 4.528±0.002 9.862±0.003 2.978±0.001 5 25 6.85 131.6±0.3 4.504±0.006 9.850±0.010 2.967±0.005 6 100 6.84 131.8±0.4 4.497±0.009 9.847±0.013 2.977±0.007 7 175 6.77 132.1±0.1 4.497±0.001 9.860±0.002 2.979±0.001 8 225 6.78 132.5±0.2 4.497±0.003 9.860±0.005 2.988±0.003 9 275 6.64 132.7±0.1 4.498±0.001 9.863±0.002 2.991±0.001

Table S1 (online resource 1) (a) continued.

No. T [°C] P [GPa] V [ų] a [Å] b [Å] c [Å] Run R25 Goethite 1 25 0.03 138.6±0.1 4.607±0.002 9.961±0.004 3.021±0.001 2 25 3.92 134.1±0.2 4.537±0.005 9.889±0.006 2.989±0.001 4 200 7.11 131.8±0.1 4.490±0.002 9.849±0.002 2.979±0.001 5 250 7.16 132.0±0.1 4.489±0.001 9.854±0.002 2.984±0.001 6 300 7.14 132.3±0.1 4.489±0.002 9.855±0.003 2.990±0.002 7 310 7.15 132.4±0.1 4.493±0.002 9.857±0.002 2.990±0.002 8 320 7.09 132.4±0.1 4.490±0.001 9.858±0.002 2.991±0.001 9 330 7.06 132.4±0.1 4.490±0.003 9.858±0.003 2.991±0.002 10 340 7.18 132.5±0.2 4.492±0.004 9.860±0.005 2.992±0.003 11 350 6.97 132.8±0.2 4.496±0.005 9.861±0.006 2.995±0.004 12 360 7.07 132.5±0.3 4.496±0.006 9.858±0.008 2.989±0.005 13 360 7.08 132.7±0.4 4.500±0.007 9.866±0.010 2.989±0.006 14 340 7.00 132.8±0.4 4.508±0.007 9.864±0.009 2.987±0.006 15 320 6.83 132.7±0.5 4.505±0.010 9.871±0.013 2.985±0.008 16 300 7.01 132.6±0.5 4.501±0.010 9.871±0.013 2.984±0.008 17 250 6.97 132.5±0.5 4.501±0.010 9.867±0.014 2.983±0.009 18 250 6.91 132.6±0.6 4.498±0.011 9.866±0.015 2.988±0.009 19 250 6.41 132.6±0.6 4.498±0.011 9.870±0.015 2.987±0.009 Run R25 ε-FeO(OH) 7 310 7.15 64.0±0.3 4.885±0.089 4.334±0.008 3.022±0.013 8 320 7.09 63.8±0.4 4.887±0.011 4.336±0.010 3.009±0.016 9 330 7.06 63.6±0.2 4.902±0.009 4.348±0.007 2.982±0.005 10 340 7.18 63.5±0.2 4.906±0.009 4.352±0.005 2.975±0.005 11 350 6.97 63.6±0.2 4.907±0.008 4.356±0.004 2.977±0.004 12 360 7.07 63.7±0.1 4.906±0.071 4.358±0.004 2.978±0.003 13 360 7.08 63.7±0.1 4.907±0.007 4.361±0.004 2.978±0.003 14 340 7.00 63.7±0.1 4.907±0.007 4.364±0.004 2.976±0.003 15 320 6.83 63.9±0.1 4.910±0.008 4.368±0.005 2.977±0.003 16 300 7.01 63.7±0.2 4.910±0.009 4.366±0.005 2.974±0.004 17 250 6.97 63.7±0.1 4.907±0.006 4.372±0.003 2.970±0.003 18 250 6.91 63.7±0.1 4.904±0.007 4.376±0.004 2.969±0.003 19 250 6.41 63.8±0.1 4.904±0.003 4.373±0.002 2.974±0.002 19b 250 6.41 63.8±0.0 4.903±0.002 4.370±0.001 2.976±0.001 20 25 0.0001 66.0±0.1 4.952±0.004 4.444±0.004 2.998±0.002 20b 25 0.0001 66.0±0.1 4.948±0.002 4.447±0.002 3.001±0.001 Run R28 Goethite 1 25 0.03 138.6±0.2 4.605±0.003 9.957±0.004 3.023±0.003 2 25 5.31 133.4±0.1 4.531±0.004 9.885±0.004 2.977±0.001 3 100 5.50 133.1±0.3 4.516±0.005 9.873±0.007 2.986±0.004 4 150 5.54 133.4±0.1 4.521±0.002 9.873±0.003 2.988±0.002 5 200 5.51 133.2±0.3 4.515±0.005 9.875±0.007 2.989±0.004 6 250 5.38 133.8±0.1 4.515±0.002 9.882±0.003 2.999±0.002 7 300 5.40 134.1±0.1 4.520±0.002 9.886±0.002 3.000±0.001 8 350 5.32 134.4±0.1 4.520±0.001 9.895±0.001 3.004±0.001 9 350 5.78 133.9±0.1 4.517±0.002 9.882±0.003 3.001±0.002 10 350 6.20 133.7±0.1 4.512±0.002 9.879±0.002 2.999±0.001 11 350 6.60 133.0±0.1 4.500±0.001 9.867±0.001 2.995±0.001 12 360 6.57 133.1±0.1 4.498±0.002 9.874±0.003 2.996±0.002 13 370 6.68 133.2±0.2 4.500±0.004 9.876±0.005 2.997±0.003 13b 370 6.68 133.0±0.1 4.503±0.002 9.866±0.002 2.993±0.002 14 380 6.83 133.1±0.2 4.506±0.003 9.869±0.005 2.993±0.003 15 390 6.79 133.1±0.2 4.503±0.005 9.875±0.006 2.993±0.004 16 400 6.74 133.3±0.2 4.510±0.004 9.874±0.006 2.993±0.003 16b 400 6.74 133.1±0.3 4.507±0.006 9.875±0.008 2.991±0.005 17 300 6.70 133.0±0.3 4.505±0.006 9.865±0.007 2.992±0.005 18 200 6.70 132.6±0.3 4.510±0.005 9.857±0.007 2.984±0.004 19 100 6.70 132.4±0.4 4.499±0.008 9.865±0.011 2.984±0.006 20 50 6.70 132.4±0.3 4.503±0.006 9.856±0.008 2.983±0.005 21 40 0.0001 137.5±0.3 4.599±0.006 9.944±0.008 3.007±0.005

Table S1 (online resource 1) (a) continued.

No. T [°C] P [GPa] V [ų] a [Å] b [Å] c [Å] Run R28 Magnetite 16b 400 6.74 576.2±0.2 8.321±0.002 17 300 6.70 576.3±0.3 8.322±0.003 18 200 6.70 574.1±0.1 8.311±0.001 19 100 6.70 572.4±0.1 8.303±0.001 20 50 6.70 573.6±0.3 8.309±0.003 21 40 0.0001 590.8±0.7 8.391±0.006 Run R28 ε-FeO(OH) 11 350 6.60 64.2±0.3 4.895±0.016 4.376±0.011 2.995±0.005 12 360 6.57 64.3±0.2 4.903±0.012 4.376±0.008 2.995±0.004 13 370 6.68 64.3±0.3 4.905±0.014 4.374±0.010 2.996±0.005 13b 370 6.68 64.2±0.2 4.905±0.013 4.371±0.009 2.996±0.004 14 380 6.83 64.2±0.2 4.907±0.013 4.377±0.009 2.990±0.004 15 390 6.79 64.4±0.2 4.923±0.011 4.377±0.008 2.986±0.003 16 400 6.74 64.3±0.3 4.921±0.014 4.385±0.010 2.981±0.004 16b 400 6.74 64.2±0.3 4.922±0.017 4.374±0.012 2.983±0.005 17 300 6.70 64.2±0.3 4.924±0.018 4.377±0.013 2.978±0.006 18 200 6.70 64.2±0.3 4.922±0.017 4.382±0.012 2.975±0.005 19 100 6.70 64.1±0.3 4.919±0.017 4.375±0.012 2.976±0.005 20 50 6.70 64.0±0.3 4.922±0.016 4.382±0.011 2.968±0.005 21 40 0.0001 65.9±0.2 4.944±0.008 4.452±0.006 2.996±0.004 Run R30 Goethite 1 25 0.03 138.6±0.2 4.610±0.004 9.952±0.006 3.022±0.004 2 25 3.30 135.4±0.1 4.559±0.003 9.906±0.003 2.999±0.001 3 50 3.22 135.5±0.2 4.559±0.004 9.919±0.006 2.997±0.003 4 100 3.23 135.7±0.2 4.559±0.003 9.910±0.005 3.003±0.003 5 150 3.19 135.9±0.2 4.554±0.003 9.916±0.004 3.010±0.003 6 200 3.18 136.0±0.2 4.556±0.003 9.916±0.004 3.011±0.002 7 200 3.75 135.6±0.1 4.544±0.001 9.912±0.002 3.011±0.001 8 200 4.27 135.0±0.2 4.536±0.003 9.897±0.004 3.006±0.002 9 200 4.83 134.4±0.3 4.527±0.005 9.885±0.008 3.002±0.004 10 200 5.28 133.7±0.1 4.521±0.002 9.879±0.004 2.994±0.002 11 200 5.85 133.3±0.1 4.516±0.003 9.873±0.004 2.989±0.002 12 200 6.36 132.8±0.1 4.505±0.001 9.865±0.002 2.987±0.001 13 250 6.44 132.9±0.2 4.506±0.003 9.864±0.004 2.988±0.003 14 300 6.42 133.2±0.1 4.505±0.003 9.873±0.004 2.994±0.002 15 310 6.53 133.1±0.1 4.500±0.002 9.879±0.002 2.994±0.002 16 325 6.67 133.2±0.1 4.504±0.002 9.873±0.002 2.996±0.002 17 350 6.66 133.5±0.1 4.508±0.003 9.876±0.004 2.998±0.001 18 375 6.64 133.4±0.2 4.505±0.004 9.886±0.006 2.996±0.004 19 400 6.63 133.5±0.5 4.468±0.009 9.921±0.013 3.011±0.009 Run R30 Magnetite 20b 425 6.69 581.5±0.6 8.347±0.005 21 450 6.77 579.8±0.4 8.338±0.003 21b 450 6.77 583.6±1.0 8.357±0.009 22 475 6.77* 578.1±0.3 8.331±0.003 Run R30 ε-FeO(OH) 17 350 6.66 64.0±0.2 4.916±0.008 4.353±0.005 2.992±0.005 18 375 6.64 64.5±0.2 4.936±0.146 4.361±0.067 2.997±0.005 19 400 6.63 64.4±0.2 4.910±0.011 4.382±0.005 2.991±0.004 20 425 6.69 64.3±0.2 4.918±0.010 4.371±0.005 2.992±0.004 20b 425 6.69 64.4±0.1 4.930±0.007 4.364±0.004 2.994±0.003 21 450 6.77 64.4±0.1 4.916±0.007 4.375±0.006 2.996±0.002 21b 450 6.77 64.2±0.1 4.917±0.003 4.371±0.002 2.989±0.001 * pressure assumed as constant

Table S1 (online resource 1) (b) Lattice parameters of MnO(OH) (groutite) as a function of P and T.

No. T [°C] P [GPa] V [ų] a [Å] b [Å] c [Å] Run R05 Groutite 1 25 0.0001 139.8±0.2 10.669±0.009 2.871±0.002 4.564±0.003 2 25 0.67 138.7±0.2 10.649±0.009 2.863±0.002 4.548±0.003 2b# 25 0.67 138.7±0.3 10.653±0.015 2.863±0.003 4.546±0.004 3 25 1.68 137.3±0.2 10.607±0.011 2.854±0.003 4.536±0.004 3b# 25 1.68 137.4±0.2 10.614±0.012 2.858±0.003 4.529±0.004 4 25 2.18 136.3±0.2 10.567±0.010 2.853±0.004 4.520±0.003 4b# 25 2.18 136.2±0.3 10.584±0.012 2.848±0.004 4.517±0.004 5 25 3.63 134.1±0.3 10.550±0.014 2.834±0.004 4.485±0.006 5b# 25 3.63 134.7±0.2 10.559±0.010 2.849±0.002 4.477±0.003 6 25 5.38 132.9±0.2 10.483±0.010 2.825±0.003 4.487±0.003 7 100 5.72 133.5±0.2 10.494±0.011 2.830±0.003 4.496±0.003 8 150 5.82 133.4±0.3 10.466±0.013 2.832±0.003 4.500±0.004 9 200 5.78 133.2±0.3 10.457±0.012 2.833±0.004 4.494±0.004 10 250 5.64 134.5±0.3 10.513±0.013 2.852±0.004 4.484±0.005 Run R06 Groutite 1 25 0.02 140.1±0.2 10.688±0.014 2.876±0.002 4.557±0.003 1b# 25 0.02 140.0±0.2 10.681±0.011 2.878±0.002 4.554±0.003 2 25 0.82 138.9±0.3 10.652±0.013 2.867±0.003 4.549±0.004 2b# 25 0.82 138.7±0.2 10.658±0.010 2.866±0.002 4.540±0.003 3 25 1.55 137.3±0.1 10.591±0.008 2.865±0.002 4.526±0.002 3b# 25 1.55 137.3±0.2 10.615±0.011 2.860±0.003 4.524±0.003 4 25 2.40 136.3±0.2 10.590±0.012 2.853±0.003 4.512±0.004 4b# 25 2.40 136.0±0.3 10.569±0.013 2.852±0.003 4.512±0.004 5 25 3.84 133.8±0.2 10.478±0.009 2.848±0.002 4.483±0.002 5b# 25 3.84 134.0±0.2 10.494±0.011 2.849±0.002 4.483±0.002 6 100 3.85 134.3±0.1 10.523±0.007 2.848±0.002 4.483±0.002 8 400 3.49 135.2±0.2 10.542±0.009 2.856±0.002 4.492±0.003 # diffraction patterns were obtained at a different position in the sample layer

Table S1 (online resource 1) (c) Lattice parameters of MnO(OH) (manganite) and its dehydration

products as a function of P and T.

No. T [°C] P [GPa] V [ų] a, c [Å] b [Å] Beta [°] Run R05 Manganite 1 25 0.0001 135.2±0.3 5.322±0.005 5.245±0.009 114.52±0.12 2 25 0.67 134.4±0.3 5.313±0.007 5.235±0.005 114.57±0.11 2b# 25 0.67 134.3±0.2 5.292±0.005 5.269±0.003 114.46±0.10 3 25 1.68 132.3±0.2 5.297±0.004 5.219±0.003 114.88±0.08 3b# 25 1.68 132.6±0.2 5.290±0.004 5.228±0.003 114.84±0.10 4 25 2.18 131.4±0.3 5.274±0.007 5.194±0.004 114.53±0.14 4b# 25 2.18 131.7±0.4 5.272±0.009 5.210±0.005 114.57±0.16 5 25 3.63 129.9±0.2 5.228±0.004 5.196±0.004 113.87±0.10 5b# 25 3.63 130.1±0.3 5.251±0.007 5.182±0.004 114.46±0.14 6 25 5.40 127.7±0.2 5.196±0.004 5.152±0.005 113.26±0.08 6b# 25 5.38 127.4±0.2 5.196±0.004 5.143±0.005 113.46±0.06 7 100 5.72 127.9±0.3 5.193±0.007 5.157±0.004 113.18±0.13 8 150 5.82 127.6±0.2 5.188±0.004 5.147±0.002 112.95±0.09 9 200 5.78 127.5±0.1 5.197±0.003 5.143±0.002 113.35±0.06 10 250 5.64 129.0±0.1 5.226±0.002 5.176±0.002 114.12±0.04 11 300 5.41 129.4±0.2 5.223±0.004 5.176±0.002 113.56±0.12 12 350 5.40 129.5±0.2 5.226±0.005 5.182±0.002 113.73±0.13 13 400 5.50 129.7±0.1 5.230±0.002 5.182±0.001 113.81±0.05 14 450 5.54 130.2±0.3 5.235±0.005 5.184±0.005 113.65±0.18 Run R05 Mn3O4 [II] 14 450 5,54 278.0±0.6 9.518±0.013 9.728±0.010 3.003±0.004 15 500 5,54* 278.5±0.6 9.517±0.016 9.726±0.003 3.009±0.004 Run R05 Manganosite 15 500 5,54* 86.7±0.1 4.425±0.003 Run R06 Manganite 1 25 0.02 135.2±0.2 5.304±0.004 5.279±0.003 114.51±0.08 1b# 25 0.02 135.5±0.3 5.310±0.006 5.280±0.005 114.50±0.12 2 25 0.82 135.1±0.2 5.316±0.004 5.257±0.005 114.58±0.08 2b# 25 0.82 134.3±0.2 5.308±0.004 5.244±0.004 114.65±0.08 3 25 1.55 132.9±0.2 5.291±0.005 5.230±0.005 114.77±0.09 3b# 25 1.55 132.6±0.2 5.286±0.003 5.224±0.003 114.72±0.06 4 25 2.40 131.6±0.3 5.262±0.006 5.215±0.006 114.25±0.10 4b# 25 2.40 132.0±0.1 5.268±0.002 5.223±0.004 114.39±0.04 5 25 3.84 130.7±0.3 5.253±0.006 5.194±0.009 114.26±0.11 5b# 25 3.84 130.0±0.2 5.242±0.004 5.183±0.003 114.09±0.06 6 100 3.85 129.9±0.2 5.242±0.004 5.177±0.003 114.13±0.06 8 400 3.49 130.9±0.2 5.253±0.005 5.191±0.004 113.97±0.08 Run R06 Manganosite 9 500 3.54 87.2±0.1 4.435±0.001 10 600 3.47 88.4±0.1 4.454±0.002 11 700 3.69 89.4±0.1 4.471±0.001 * pressure assumed as constant # diffraction patterns were obtained at a different position in the sample layer