Data Item _atom_site.aniso_B[1][2]


Item name
Category name
Attribute name
Required in PDB entries
Used in currrent PDB entries

Item Description

The [1][2] element of the anisotropic atomic displacement matrix B, which appears in the structure-factor term as: T = exp{-1/4 sumi[sumj(Bij hi hj a*i a*j)]} h = the Miller indices a* = the reciprocal space cell lengths These matrix elements may appear with atomic coordinates in the ATOM_SITE category, or they may appear in the separate ATOM_SITE_ANISOTROP category, but they may not appear in both places. Similarly, anisotropic displacements may appear as either B's or U's, but not as both. The unique elements of the real symmetric matrix are entered by row. The IUCr Commission on Nomenclature recommends against the use of B for reporting atomic displacement parameters. U, being directly proportional to B, is preferred.

Additional Descriptive Information for Depositors

 The [1][2] element of the matrix that defines the overall anisotropic displacement model if one was refined for this structure

Data Type

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Data type detail
float item types are the subset of numbers that are the floating numbers.
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Regular expression


Subcategory Name Subcategory Description
matrix The collection of elements of a matrix.