Expand description
Element symbol and atomic number lookup.
Both lookups cover hydrogen through uranium (Z = 1..=92) plus the
hydrogen isotopes deuterium (“D”) and tritium (“T”) which both
map to Z = 1 since they share hydrogen’s nucleon charge. The
reverse lookup (atomic_number_to_symbol) returns the standard
“H” for Z = 1; callers that need to distinguish isotopes do so out
of band (e.g. an isotope metadata key on the frame, or by
storing “D” / “T” as the per-atom symbol).
The mapping is informational, not binding. The CON spec does not
mandate that an atom’s symbol correspond to any periodic-table
element; consumers commonly store ghost atoms (e.g. for QM/MM
link atoms, virtual sites, dummy positions in NEB chains) with
whatever symbol fits their workflow. Unknown inputs return a
stable sentinel: symbol_to_atomic_number returns 0 for
unknown symbols and atomic_number_to_symbol returns “X” for
unknown atomic numbers.
The same lookup is exposed to C/C++ via crate::ffi::rkr_symbol_to_z
and crate::ffi::rkr_z_to_symbol so downstream tools can drop
their own copies of the periodic table.
Functions§
- atomic_
number_ to_ symbol - Returns the chemical symbol for an atomic number, or “X” if unknown.
- symbol_
to_ atomic_ number - Returns the atomic number for a chemical symbol, or 0 if unknown.