m). The unit cell parameters of the rhombohedral structure are a = 2.7170 (±0.0070) Å, c = 7.0535 (±0.0141) Å, and c/a = 2.5961 (±0.0085).Supporting information for Lin et al. (2003) Proc. Natl. Acad. Sci. USA, 10.1073/pnas.252782399.
Table 1. Observed and calculated x-ray diffraction peaks of (Mg0.25,Fe0.75)O at 75 GPa and 300 K
h | k | l | d obs, Å | d calc, Å | d obs – dcalc, Å | Normalized Iobs |
0 | 0 | 3 | 2.3498 | 2.3512 | –0.0014 | 7 |
1 | 0 | 1 | 2.2354 | 2.2320 | 0.0033 | 8 |
1 | 0 | 2 | 1.9578 | 1.9573 | 0.0005 | 100 |
1 | 0 | 4 | 1.4081 | 1.4111 | –0.0030 | 18 |
1 | 1 | 0 | 1.3550 | 1.3585 | –0.0034 | 6 |
1 | 0 | 5 | 1.2105 | 1.2099 | 0.0006 | 2 |
1 | 1 | 3 | 1.1775 | 1.1763 | 0.0013 | 5 |
2 | 0 | 2 | 1.1168 | 1.1160 | 0.0007 | 2 |
Le Bail and Rietveld refinements, performed with the GSAS program (1, 2), reveal that the sample is in the rhombohedral structure (Rm). The unit cell parameters of the rhombohedral structure are a = 2.7170 (±0.0070) Å, c = 7.0535 (±0.0141) Å, and c/a = 2.5961 (±0.0085).
1. Larson, A. C. & Von Dreele, R. B. (1988) GSAS Manual (Los Alamos Natl. Lab., Los Alamos, NM), Report LAUR 86-748.
2. Toby, B. H. (2001) J. Appl. Crystallogr. 34, 210–213.