checkCIF procedure
PLAT242
PLAT242 Type_2 Test for Unusually Low U(eq) as compared with bonded neighbours
The U(eq) value of an atom is compared with the average U(eq) for non-hydrogen atoms bonded to it. Large differences may indicate that the wrong atom type was assigned (e.g. N instead of O). False alarms may occur for terminal groups such as the t-butyl moiety.