Table 5 Structure parameters derived from the fitting of Fe K-edge EXAFS spectra of hematite and Al-doped hematite samples.
Hem | AlH1 | AlH3 | AlH5 | AlH7 | AlH9 | AlH11 | AlH13 | |
---|---|---|---|---|---|---|---|---|
Fe-O1 (1) | ||||||||
CN | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
R (Å) | 1.933 (15) | 1.942 (17) | 1.939 (10) | 1.939 (11) | 1.942 (12) | 1.939 (12) | 1.937 (11) | 1.938 (12) |
σ2 (Å) | 0.0047 (15) | 0.0052 (18) | 0.0036 (8) | 0.0036 (9) | 0.0037 (11) | 0.0034 (10) | 0.0038 (9) | 0.0036 (9) |
Fe-O1 (2) | ||||||||
CN | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
R (Å) | 2.078 (21) | 2.076 (27) | 2.090 (17) | 2.088 (19) | 2.089 (22) | 2.089 (21) | 2.087 (18) | 2.093 (21) |
σ2 (Å) | 0.0064 (24) | 0.0087 (43) | 0.0066 (18) | 0.0069 (9) | 0.0072 (25) | 0.0067 (22) | 0.0063 (17) | 0.0068 (19) |
Fe-FeF | ||||||||
CN | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
R (Å) | 2.854 (35) | 2.855 (32) | 2.876 (29) | 2.883 (30) | 2.887 (36) | 2.894 (50) | 2.931 (95) | 2.969 (40) |
σ2 (Å) | 0.0019 (10) | 0.0016 (24) | 0.0024 (15) | 0.0023 (27) | 0.00323 (31) | 0.0033 (50) | 0.0078 (62) | 0.0051 (40) |
Fe-FeE | ||||||||
CN | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
R (Å) | 2.975 (14) | 2.977 (17) | 2.987 (16) | 2.992 (18) | 2.998 (21) | 2.991 (25) | 2.979 (95) | 2.987 (55) |
σ2 (Å) | 0.0019 (10) | 0.0025 (13) | 0.0035 (13) | 0.0035 (14) | 0.0034 (16) | 0.0041 (23) | 0.0063 (17) | 0.0118 (46) |
Fe-FeC (1) | ||||||||
CN | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |
R (Å) | 3.391 (11) | 3.397 (13) | 3.397 (10) | 3.399 (11) | 3.403 (13) | 3.398 (13) | 3.398 (13) | 3.410 (17) |
σ2 (Å) | 0.0038 (8) | 0.0044 (9) | 0.0050 (7) | 0.0051 (8) | 0.0052 (9) | 0.0052 (9) | 0.0069 (11) | 0.0067 (12) |
Fe-FeC (2) | ||||||||
CN | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
R (Å) | 3.687 (13) | 3.683 (14) | 3.685 (12) | 3.688 (14) | 3.693 (16) | 3.686 (16) | 3.688 (17) | 3.679 (22) |
σ2 (Å) | 0.0086 (9) | 0.0092 (11) | 0.0105 (10) | 0.0111 (11) | 0.0114 (13) | 0.0112 (13) | 0.0133 (16) | 0.0147 (23) |
E0 (eV) | −2 (2) | −1 (2) | 0 (2) | 1 (2) | 1 (2) | 1 (2) | 0 (2) | 1 (2) |
Chi Sq | 44 | 72 | 797 | 1118 | 128 | 63 | 22 | 21 |
R-factor | 0.0048 | 0.0045 | 0.0033 | 0.0038 | 0.0049 | 0.0048 | 0.0048 | 0.008 |