An extremely low R-factor from a tiny crystal
A structure originally published as a polysynthetic triclinic twin has been redetermined from a miniscule untwinned specimen carefully separated from the original sample. Even though the crystal was tiny (0.07 × 0.03 × 0.01 mm3), data collected on the RAPID II using a Mo sealed tube source produced a structure with extremely low R-factors: R1 = 0.0088 (I > 2σ(I), 399 reflections), wR2 = 0.0187 (all data, 407 reflections).
Reference: A.R. Kampf, : Mineralogical Magazine, April 2009, Vol. 73(2), pp. 251-255.
|
Diffractometer |
Rigaku RAPID II |
The structure of Ba2F2(S6+O3S2-). Ba atoms are in blue, F in green, S in red and O in white. | ||
|
Source |
Sealed tube | |||
|
Radiation |
Mo Kα | |||
|
Power | 50kv / 40mA | |||
|
Temperature |
298(2) K | |||
|
Formula |
Ba2F2(S6+O3S2-) | |||
|
Space group |
C2/m | |||
|
a |
15.3172(5) Å | |||
|
b |
4.5898(1) Å | |||
|
c |
4.6320(2) Å | |||
|
β |
101.449(1)° | |||
|
Z |
2 | |||
|
Vol |
319.17(2) Å3 | |||
|
Density |
4.419 g/cm3 | |||
|
Abs. coeff. |
12.886 mm-1 | |||
|
F(000) |
372 | |||
|
Crystal size |
0.07 × 0.03 × 0.01 | |||
|
θ range |
4.49 - 27.44° | |||
|
Reflns.(Total) |
3749 | |||
|
Reflns. (Unique) |
407 | |||
|
R(int) |
0.025 | |||
|
Parameters |
40 | |||
|
R1 (I>2σI) |
0.0088 | |||
|
wR2 (all data) |
0.0187 | |||
|
GoOF |
1.15 |
Tags: small crystals, long exposures,