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:

  1. Reasonable Z values are guessed and could either accepted or superseded by the value entered.

  2. 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