Chemical formula type¶
Warning
This module is preliminary! API may change or disappear in the future.
-
class
ase.formula.
Formula
(formula: str = '', *, strict: bool = False, _tree: Union[str, Tuple[Tree, int], List[Tree]] = None, _count: Dict[str, int] = None)[source]¶ Chemical formula object.
Parameters: - formula (str) – Text string representation of formula. Examples:
'6CO2'
,'30Cu+2CO'
,'Pt(CO)6'
. - strict (bool) – Only allow real chemical symbols.
Examples
>>> from ase.formula import Formula >>> w = Formula('H2O') >>> w.count() {'H': 2, 'O': 1} >>> 'H' in w True >>> w == 'HOH' True >>> f'{w:latex}' 'H$_{2}$O' >>> w.format('latex') 'H$_{2}$O' >>> divmod(6 * w + 'Cu', w) (6, Formula('Cu'))
Raises: ValueError
– on malformed formula-
count
() → Dict[str, int][source]¶ Return dictionary mapping chemical symbol to number of atoms.
Example
>>> Formula('H2O').count() {'H': 2, 'O': 1}
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reduce
() → Tuple[ase.formula.Formula, int][source]¶ Reduce formula.
Returns: - formula (Formula) – Reduced formula.
- n (int) – Number of reduced formula units.
Example
>>> Formula('2H2O').reduce() (Formula('H2O'), 2)
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stoichiometry
() → Tuple[ase.formula.Formula, ase.formula.Formula, int][source]¶ Reduce to unique stoichiomerty using “chemical symbols” A, B, C, …
Examples
>>> Formula('CO2').stoichiometry() (Formula('AB2'), Formula('CO2'), 1) >>> Formula('(H2O)4').stoichiometry() (Formula('AB2'), Formula('OH2'), 4)
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format
(fmt: str = '') → str[source]¶ Format formula as string.
Formats:
'hill'
: alphabetically ordered with C and H first'metal'
: alphabetically ordered with metals first'abc'
: count ordered first then alphabetically ordered'latex'
: LaTeX representation'html'
: HTML representation'rest'
: reStructuredText representation
Example
>>> Formula('H2O').format('html') 'H<sub>2</sub>O'
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__format__
(fmt: str) → str[source]¶ Format Formula as str.
Possible formats:
'hill'
,'metal'
,'abc'
,'latex'
,'html'
,'rest'
.Example
>>> f = Formula('OH2') >>> '{f}, {f:hill}, {f:latex}'.format(f=f) 'OH2, H2O, OH$_{2}$'
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__contains__
(f: Union[str, Formula]) → bool[source]¶ Check if formula contains chemical symbols in f.
Type of f must be str or Formula.
Example
>>> 'OH' in Formula('H2O') True
- formula (str) – Text string representation of formula. Examples: