Alert level A THETM01_ALERT_3_A The value of sine(theta_max)/wavelength is less than 0.550.
Calculated sin(theta_max)/wavelength = 0.4980 PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low ....... 0.935 Note PLAT043_ALERT_1_A Calculated and Reported Mol. Weight Differ by .. 51.94 Check PLAT051_ALERT_1_A Mu(calc) and Mu(CIF) Ratio Differs from 1.0 by . 45.30 % PLAT122_ALERT_1_A No _symmetry_space_group_name_H-M Given .
PLAT 122 is just the missing entry for the space group (not every software inserts it automatically)
PLAT 051 and 043 are related and indicate that the formula that is provided during the refinement is not correct, i.e. that the unit cell content does not equal Z* the formula.
The other two alerts indicate an incomplete data collection, e.g. the crystal did not diffract verry well. You are missing reflections (only 93% are covered) and you don't have reflections at high angles (high resolution), which means that you might need to recollect the data.
The Alerts from cif check are not always meant to be correctable or unavoidable depending on your crystal. The Alerts are there for you to be aware of possible problems with the structure. They are meant to be understood and addressed if possible and then to be explained when they are unavoidable. The THETM01_ALERT_3_A alert might be that your crystals do not diffract to high angles and may never diffract to high angles no matter how many crystals you try because of extreme disorder in the lattice that causes too much deconstructive interference. Materials such as some MOF's often have poor diffraction at high angles and so you may not have integrated to the preferred resolution of 0.83 angstroms, but instead to 1 angstrom because that is the best data you can obtain. The PLAT029 alert is because Acta prefers that you have collected at least 95% of the data. Here you only have 93.5% of the data. Is it because you did not collect a full data set or because reflections are missing from the high angle data because they were too weak to be counted? Is this situation avoidable with another data collection or is 93.5% of the possible data enough to refine a chemically relevant crystal structure for the purposes in which you intend to use it? The PLAT 043 and 051 alerts have to do with the reported formula either it is wrong or your formula is correct but not all the atoms are represented in the structure model. This could happen because you included solvate molecule in the formula, but "squeezed" them from the structure.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science