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Line 56 -2794 21139 6600
Line 57 2876 15736 11820
Line 58 -14029 20018 -10310
Line 59 -22477 3450 6965
Line 60 -806 -4365 16672
Line 61 14642 -18918 3566
Line 62 23341 -2014 -13035
Line 63 1740 5536 -22837
Each line is either a blank line, a block header line
or a data record containing multiple fields of
information about the structure. The SMD file is
broken down into several blocks of information.
The header for each block starts with a > sign.
Individual fields are delimited by space(s) or a tab.
The fields in the SMD format file used by Chem3D
Pro are discussed below:
1. Line 1 starts the block named STRT. This
block contains the molecule name. The
molecule name is the file name when the file
was created using Chem3D Pro.
2. Line 2 starts the block named DTCR. The
information in this line includes the name of
the application that created the file and the date
and time when the file was generated.
3. Line 3 starts the block named CT which
contains the connection table of the
compound(s). Also on this line is a 10 character
description of the connection table. This will
be the same as the file name when the file is
generated using Chem3D Pro. Finally, the
number of records contained within the CT
block is indicated, 39 in the above example.
4. Line 4 of the CT Block contains four fields.
The first field is the number of atoms, the
second field is the number of bonds, the third
field is the FORTRAN format for the number
of atoms, and the fourth field is the
FORTRAN format for the number of bonds.
5. Lines 5–23 of the CT Block each contain 4
fields describing an atom. The first field is the
element symbol (first letter uppercase, second
lowercase). The second field is the total
number of hydrogens attached to the atom, the
third field is the stereo information about the
atom and the fourth field is the formal charge
of the atom.
NOTE: If the file is created using Chem3D Pro, the
number of hydrogens, the stereo information and the
formal charge fields are not used, and will always
contain zeros.
6. Lines 24–42 of the CT Block each contains 3
fields describing a bond between the two
atoms. The first field is the serial number of the
atom from which the bond starts, the second
field is the serial number of atom where the
bond ends, and the third field is the bond
order.
7. Line 43 starts the block named CO, The
information in this block includes the Cartesian
coordinates of all the atoms from the CT block
and indicates the type of coordinates used,
Angstroms in this example. Also in this line is
the number of lines in the block, 20 in this
example.
8. Line 44 contains two fields. The first field
contains the exponent used to convert the
coordinates in the lines following to the
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