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, format: str = '', _tree: Union[str, Tuple[Tree, int], List[Tree]] = None, _count: Dict[str, int] = None)[source]¶ Chemical formula object.
- Parameters
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
-
convert
(fmt: str) → ase.formula.Formula[source]¶ Reformat this formula as a new Formula.
Same formatting rules as Formula(format=…) keyword.
-
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)
-
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'reduce'
: Reduce and keep order (ABBBC -> AB3C)'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'
,'reduce'
,'latex'
,'html'
,'rest'
.Example
>>> f = Formula('OH2') >>> '{f}, {f:hill}, {f:latex}'.format(f=f) 'OH2, H2O, OH$_{2}$'
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static
from_dict
(dct: Dict[str, int]) → ase.formula.Formula[source]¶ Convert dict to Formula.
>>> Formula.from_dict({'H': 2}) Formula('H2')
-
static
from_list
(symbols: Sequence[str]) → ase.formula.Formula[source]¶ Convert list of chemical symbols to Formula.
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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.
Examples
>>> 'OH' in Formula('H2O') True >>> 'O2' in Formula('H2O') False
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__eq__
(other) → bool[source]¶ Equality check.
Note that order is not important.
Example
>>> Formula('CO') == Formula('OC') True
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__add__
(other: Union[str, Formula]) → ase.formula.Formula[source]¶ Add two formulas.
-
__mul__
(N: int) → ase.formula.Formula[source]¶ Repeat formula \(N\) times.