Inorganic Chemistry

Code Examples

import numpy as np
from typing import List, Dict, Tuple
from enum import Enum

class Geometry(Enum):
    OCTAHEDRAL = "octahedral"
    TETRAHEDRAL = "tetrahedral"
    SQUARE_PLANAR = "square_planar"
    LINEAR = "linear"

class CoordinationCompound:
    def __init__(self, metal: str, oxidation_state: int, 
                 ligands: List[str], geometry: Geometry):
        self.metal = metal
        self.oxidation_state = oxidation_state
        self.ligands = ligands
        self.geometry = geometry
        self.coordination_number = len(ligands)

    def calculate_cfse(self, d_electrons: int) -> float:
        cfse_values = {
            Geometry.OCTAHEDRAL: {'t2g': -0.4, 'eg': 0.6},
            Geometry.TETRAHEDRAL: {'e': -0.6, 't2': 0.4},
            Geometry.SQUARE_PLANAR: {'dx2_y2': 1.23, 'dxy': -0.46}
        }
        return cfse_values.get(self.geometry, {})

    def get_spectrochemical_position(self) -> List[str]:
        spectrochemical_series = [
            'I-', 'Br-', 'Cl-', 'F-', 'OH-', 'H2O', 
            'NH3', 'en', 'NO2-', 'CN-', 'CO'
        ]
        return sorted(self.ligands, 
                      key=lambda x: spectrochemical_series.index(x) 
                      if x in spectrochemical_series else 99)

    def determine_high_spin_low_spin(self, pairing_energy: float) -> str:
        cfse_octahedral = {'t2g': -0.4, 'eg': 0.6}
        return "high_spin" if pairing_energy > cfse_octahedral['t2g'] * 10 else "low_spin"

complex = CoordinationCompound("Fe", 3, ['NH3', 'NH3', 'NH3', 'NH3', 'NH3', 'NH3'], 
                                 Geometry.OCTAHEDRAL)
print(f"Coordination Number: {complex.coordination_number}")
print(f"Ligand Strength: {complex.get_spectrochemical_position()}")

Best Practices

1. Always determine oxidation states correctly before analyzing electronic structure
2. Apply crystal field theory consistently for octahedral vs tetrahedral complexes
3. Consider both sigma-donor and pi-acceptor/donor properties of ligands
4. Use proper naming conventions for coordination compounds (IUPAC)
5. Account for Jahn-Teller distortions in d9 and high-spin d4 complexes
6. Validate structures with spectroscopic data and crystallography when possible
7. Consider kinetic vs thermodynamic stability in reaction products
8. Understand the role of counter ions and solvation effects
9. Apply 18-electron rule as a guideline for organometallic stability
10. Consider relativistic effects for heavier transition metals