SYSTEM-S FORMULA & Z
SYSTEM-S TOOLS
PLATON HOMEPAGE
FORMULA
The Formula instruction specifies the atom types and their number in
the molecule. Along with Z it determines the unit cell content.
The formula can be changed during the structure determination process.
Elements can be added when needed.
Examples:
FORMULA C10H10O1
FORMULA C 10 H 10 O 1
The latter format should be used to eliminate unwanted element types
(either obsolete or introduced as a type error).
Z
Z should be specified such that, along with the formula, it represents
the unit cell contents.
Notes:
- Reasonable Z values are guessed and could either accepted or
superseded by the value entered.
- In the absence of any prior knowledge of the contents of the
unit cell the formula (C1H2)n can be attempted in an attempt to solve
a structure by Direct Methods (e.g. SHELXS).
19-jan-1999 A.L.Spek