The SPF-format is a card image oriented file. The first four characters on a card specify the nature of the data that follow on that card. Data that are not needed for the current program are simply skipped. All data are free format.
TITL
This text may be used for various titleing purposes. It may be overridden at any time by another TITL instruction.
CELL
Optional wavelength and cell parameters in Angstroms and degrees respectively. No CELL card is needed for Angstrom data input. The wavelength is used for the calculation of the linear absorption coefficient.
CESD
This optional card specifies standard deviations in the cell parameters. No CESD card is needed for Angstrom data. The cell e.s.d. is combined with the coordinate e.s.d. for the calculation of the e.s.d. in derived parameters.
SPGR
Space group symbol. See Space Groups for more details.
LATT
First parameter specifies the Bravais lattice type and the second whether the lattice is acentric or centric.
SYMM
Symmetry operation. See Space Groups.
ATOM
This specifies the positional parameters, the population and their estimated standard deviations. The atom_name should conform some rules in order to be acceptable since it is interpreted. The first one or two characters should correspond to an element name known to the program (see Appendix 3). The number of characters of the element type and the attached digital number cannot exceed four. ' and " are allowed as part of an atom name. Labels not conforming with the PLATON-rules are modified in a new label including the symbol #. The atom-name may contain parentheses enclosing the numerical part.
UIJ
Anisotropic thermal parameters. Note the order of the
components that is the same as in SHELXL93 but often different in
other systems (such as the XRAY and XTAL systems).
TF = exp[-2*pi**2(U11*H**2(A*)**2+...+2*U12*H*K*(A*)(B*)+...)]
SUIJ
Estimated standard deviations for the anisotropic thermal parameters.
U
Isotropic temperature factor along with its associate standard deviation.
BIJ
Anisotropic thermal parameters. Note the order of the
components.
TF = exp[-(Beta11*H**2+Beta22*K**2+...+2*Beta12*H*K+...)] Definition: Beta11 = 2*pi**2*astar**2 Beta12 = 2*pi**2*astar*bstar.
SBIJ
Estimated standard deviations for the anisotropic thermal parameters.
B
Isotropic temperature factor along with its associate
standard deviation.
Definition: B = 8*pi**2*U
TRNS
Facility to influence the applied symmetry operation for the first atom in a new residue. (see terms and notations)
TRNS
When placed in front of an ATOM card this instruction will transform the input coordinates on that card by the named symmetry operation: n is the number of the symmetry operation and k,l,m are the translations. (see terms and notations)
TRNS
Transformation matrix on cell axis and origin shift to be
applied to the data following (CELL parameters, atomic
coordinates and thermal parameters).
Example: TITL NI-COMPOUND CELL NI .123 .544 -.176 1 .001 .002 .001 0.0 UIJ NI .011 .013 .025 -.011 .004 .009 SUIJ NI .001 .001 .002 .002 .002 .001 ATOM C1 .345 .675 -.334 1 .010 .009 .005 0.0 U C1 0.04 0.01 (etc)