CheckCIF-PLAT071-080
PLAT071 Type_1 Test for uninterpretable labels
The CIF contains labels posing problems for PLATON/CHECK. Example: label HN1 with no scattering type information supplied. Validation is aborted.
(http://journals.iucr.org/services/cif/checking/PLAT071.html)
警告原因：有原子标记不易理解。
解决策略：将原子标记改成“元素种类”+“序号”的格式。
PLAT072 Type_2 Test for extreme first weighting parameter (SHELXL)
The first parameter on the SHELXL weighting line has an exceptionally large value. This may indicate either improper reflection s.u.'s or an unresolved problem such as missed twinning.
(http://journals.iucr.org/services/cif/checking/PLAT072.html)
警告原因：权重因子中第一个数值较大，可能由于某些点拟合误差较大或者孪晶。
解决策略：OMIT掉误差较大的点或者按孪晶精修。
PLAT073 Type_1 Test for inconsistency 'constr' versus 'H-Atoms refined'
The structure contains refined hydrogen atoms. However the data item _refine_ls_hydrogen_treatment has the value 'constr'. The value 'mixed' is more appropriate.
(http://journals.iucr.org/services/cif/checking/PLAT073.html)
警告原因：结构中有氢原子被精修，CIF中_hydrogen_treatment项为constr。
解决策略：CIF中_hydrogen_treatment项为mixed。
PLAT074 Type_1 Test for Occupancy equal 0.0
The CIF contains an atom with occupacy less than 0.0001
(http://journals.iucr.org/services/cif/checking/PLAT074.html)
警告原因：CIF中包含原子占有率约为0.
解决策略：仔细检查结构模型，删除占有率为0的原子或者改正结构模型。
PLAT075 Type_1 Test for Occupancy greater than 1.0
The CIF contains an atom with Occupancy greater than 1.0.
(http://journals.iucr.org/services/cif/checking/PLAT075.html)
警告原因：某原子占有率远大于1。
解决策略：一般都是误改，将改原子占有率改成正常值即可。
PLAT076 Type_1 Test for Occupancy less than 1.0 for atom on special position
The CIF contains an atom sitting on a special position with occupancy specified as less than 1.0. This is often an error and the result of the confusion of the notions 'occupancy' and 'population parameter'. The first should be 1.0 for a fully occupied site. The latter multiplies the site-symmetry with the occupancy. Thus, for a fully occupied site on a mirror plane the site-symmetry will be 0.5 * 1.0 = 0.5.
Note: a wrong occupancy number will lead to an incorrect expected chemical formula.
(http://journals.iucr.org/services/cif/checking/PLAT076.html)
警告原因：特殊位置上原子占有率小于1。
解决策略：一般都是误改，将改原子占有率改成正常值即可。
PLAT077 Type_4 Test for Non-Integral # of atoms in Unit Cell
The unit-cell contains a non-integer number of atoms of a given atom type. Valid reasons include partially occupied (solvent) sites and substitutional disorder.
(http://journals.iucr.org/services/cif/checking/PLAT077.html)
警告原因：单胞中有非整数的原子。
解决策略：检查一下是否有原子误改了占有率并改正。否则需有合理解释，如部分溶剂或者取代无序等等。
PLAT078 Type_1 Test for inconsistency 'geom' versus 'no H-Atoms'
The structure contains no hydrogen atoms. However the data item _atom_sites_solution_hydrogen had the value 'geom'. This value is likely the SHELXL default and should be replaced by '.'.
(http://journals.iucr.org/services/cif/checking/PLAT078.html)
警告原因：结构中不存在氢原子，但是_atom_sites_solution_hydrogen值为'geom'.。
解决策略：检查是否遗忘加氢，否则将_atom_sites_solution_hydrogen值改为句点'.'。将_solution_hydrogens项和_hydrogen_treatment 项改成none
PLAT079 Type_1 Test for inconsistency 'mixed' versus 'no H-Atoms'
The structure contains no hydrogen atoms. However the data item _refine_ls_hydrogen_treatment has the value 'mixed'. This value is likely the SHELXL default and should be replaced by '.'.
(http://journals.iucr.org/services/cif/checking/PLAT079.html)
警告原因：结构中不存在氢原子，但是_atom_sites_solution_hydrogen值为'geom'.。
解决策略：检查是否遗忘加氢，否则将_atom_sites_solution_hydrogen值改为句点'.'。将_solution_hydrogens项和_hydrogen_treatment 项改成none
PLAT080 Type_2 Test maximum shift/error
Convergence of the refinement is proved with a close to zero shift/error value for all refined parameters. Such a convergence is easily achieved with a few additional refinement cycles at little cost.
Note: Some SHELXL-97 versions do not allow for negative Flack parameter values. Convergence in such a case may be never reached because the Flack parameter value is reset to zero.
(http://journals.iucr.org/services/cif/checking/PLAT080.html)
例：PLAT080_ALERT_2_A Maximum Shift/Error ..... 0.37
警告原因：精修偏移值较大(数据不收敛)。
解决策略：增加精修轮数(即将ins中L.S.后的数值改大)再精修，如果不行需要检查结构模型是否有问题，是否存在非正定，末端甲基类似基团是否存在旋转等。
