Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Unit cell type

Packing of the unit cell.

Look up the number of nearest neighbours around an atom for the common cubic and close-packed structures. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Coordination number

Nearest neighbours touching a central atom.

• Bond, orbital, and structure rules are simplified representations. Resonance, relativistic effects, electron correlation, molecular geometry, oxidation state, and the measurement or computational method affect tabulated and predicted values.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Ionic Radius Lookup

  Look up a Shannon effective ionic radius for a common six-coordinate ion; ionic radius depends on oxidation state and coordination number.

• Hybridization Lookup

  Look up the orbital hybridization of a central atom from its steric number (bonded atoms plus lone pairs).

• Madelung Constant Lookup

  Look up the electrostatic Madelung constant for common ionic crystal structures.