Chemistry Formula Compendium

This is a broad, undergraduate-to-early-graduate chemistry formula compendium built from standard chemistry references, Wikipedia formula pages, and chemistry course resources. No single file can literally contain every equation ever published in chemistry, but this sheet is designed to be thorough across General Chemistry, Organic Chemistry, Physical Chemistry, Thermodynamics, Inorganic Chemistry, and Analytical Chemistry. We will be expanding and hopefully one day have all chemistry formulas!

Total formulas listed: 209

Equation Name	Equation	ChemSubject	Link
Density	`ρ = m / V`	General Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
Specific Gravity	`SG = ρ_substance / ρ_reference`	General Chemistry, Analytical Chemistry	wikipedia.org
Amount of Substance from Mass	`n = m / M`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Amount of Substance from Particles	`n = N / N_A`	General Chemistry, Physical Chemistry	wikipedia.org
Molar Mass	`M = m / n`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Mass Percent	`mass % = (mass solute / mass solution) × 100`	General Chemistry, Analytical Chemistry	wikipedia.org
Volume Percent	`vol % = (volume solute / volume solution) × 100`	General Chemistry, Analytical Chemistry, Organic Chemistry	wikipedia.org
Parts per Million	`ppm = (mass solute / mass solution) × 10^6`	Analytical Chemistry, General Chemistry	wikipedia.org
Parts per Billion	`ppb = (mass solute / mass solution) × 10^9`	Analytical Chemistry, General Chemistry	wikipedia.org
Molarity	`c = n / V`	General Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
Molality	`b = n_solute / m_solvent(kg)`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Formality	`F = formula weight units / L solution`	Analytical Chemistry, General Chemistry	wikipedia.org
Normality	`N = equivalents / L solution`	Analytical Chemistry, General Chemistry	wikipedia.org
Mole Fraction	`x_i = n_i / Σn_j`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Molality–Molarity Approximation	`M ≈ (1000 ρ w / M_s) / [1000 + b M_s]`	Analytical Chemistry, Physical Chemistry	libretexts.org
Dilution Equation	`C_1 V_1 = C_2 V_2`	General Chemistry, Analytical Chemistry	wikipedia.org
Equivalent Weight	`Eq wt = molar mass / n-factor`	Analytical Chemistry, General Chemistry, Inorganic Chemistry	libretexts.org
Percent Yield	`% yield = (actual yield / theoretical yield) × 100`	General Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Percent Error	`% error = \|experimental − true\| / true × 100`	General Chemistry, Analytical Chemistry	wikipedia.org
Empirical Formula Percent Composition	`% element = (mass of element in 1 mol compound / molar mass compound) × 100`	General Chemistry	libretexts.org
Boyle’s Law	`P_1 V_1 = P_2 V_2`	General Chemistry, Physical Chemistry	wikipedia.org
Charles’s Law	`V_1 / T_1 = V_2 / T_2`	General Chemistry, Physical Chemistry	wikipedia.org
Gay-Lussac’s Law	`P_1 / T_1 = P_2 / T_2`	General Chemistry, Physical Chemistry	wikipedia.org
Avogadro’s Law	`V_1 / n_1 = V_2 / n_2`	General Chemistry, Physical Chemistry	wikipedia.org
Combined Gas Law	`P_1 V_1 / T_1 = P_2 V_2 / T_2`	General Chemistry, Physical Chemistry	wikipedia.org
Ideal Gas Law	`P V = n R T`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Dalton’s Law of Partial Pressures	`P_total = ΣP_i`	General Chemistry, Physical Chemistry	wikipedia.org
Partial Pressure from Mole Fraction	`P_i = x_i P_total`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Amagat’s Law of Partial Volumes	`V_total = ΣV_i`	Physical Chemistry, Thermodynamics	wikipedia.org
Graham’s Law	`r_1 / r_2 = √(M_2 / M_1)`	General Chemistry, Physical Chemistry	wikipedia.org
Compressibility Factor	`Z = P V / (n R T)`	Physical Chemistry, Thermodynamics	wikipedia.org
van der Waals Equation	`(P + a n^2 / V^2)(V − n b) = n R T`	Physical Chemistry, Thermodynamics	wikipedia.org
Virial Equation of State	`Z = 1 + B/V_m + C/V_m^2 + ...`	Physical Chemistry, Thermodynamics	wikipedia.org
Root-Mean-Square Speed	`u_rms = √(3 R T / M)`	General Chemistry, Physical Chemistry	wikipedia.org
Average Molecular Speed	`u_avg = √(8 R T / (π M))`	Physical Chemistry, General Chemistry	wikipedia.org
Most Probable Speed	`u_mp = √(2 R T / M)`	Physical Chemistry	wikipedia.org
Average Translational Kinetic Energy (per molecule)	`⟨E_k⟩ = (3/2) k_B T`	General Chemistry, Physical Chemistry	wikipedia.org
Average Translational Kinetic Energy (per mole)	`⟨E_k⟩ = (3/2) R T`	General Chemistry, Physical Chemistry	wikipedia.org
Specific Heat Equation	`q = m c ΔT`	General Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Molar Heat Equation	`q = n C_m ΔT`	General Chemistry, Thermodynamics	wikipedia.org
Calorimeter Heat	`q_cal = C_cal ΔT`	General Chemistry, Analytical Chemistry, Thermodynamics	wikipedia.org
Reaction Heat from Calorimetry	`q_rxn = −q_surroundings`	General Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
First Law of Thermodynamics	`ΔU = q + w`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Pressure–Volume Work (constant external pressure)	`w = −P_ext ΔV`	Physical Chemistry, Thermodynamics	wikipedia.org
Reversible Expansion/Compression Work (ideal gas, isothermal)	`w = −n R T ln(V_2 / V_1)`	Physical Chemistry, Thermodynamics	wikipedia.org
Enthalpy Definition	`H = U + P V`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Reaction Enthalpy from Formation Enthalpies	`ΔH°_rxn = ΣνΔH°_f(products) − ΣνΔH°_f(reactants)`	General Chemistry, Physical Chemistry, Thermodynamics, Inorganic Chemistry, Organic Chemistry	wikipedia.org
Bond Enthalpy Approximation	`ΔH_rxn ≈ ΣD(bonds broken) − ΣD(bonds formed)`	General Chemistry, Organic Chemistry, Physical Chemistry	wikipedia.org
Entropy Definition (reversible)	`dS = δq_rev / T`	Physical Chemistry, Thermodynamics	wikipedia.org
Entropy Change (isothermal ideal gas expansion)	`ΔS = n R ln(V_2 / V_1)`	Physical Chemistry, Thermodynamics	wikipedia.org
Gibbs Free Energy	`G = H − T S`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Helmholtz Free Energy	`A = U − T S`	Physical Chemistry, Thermodynamics	wikipedia.org
Gibbs Free Energy Change	`ΔG = ΔH − T ΔS`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Reaction Free Energy	`ΔG = ΔG° + R T ln Q`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Free Energy–Equilibrium Relation	`ΔG° = −R T ln K`	Physical Chemistry, Thermodynamics, General Chemistry, Analytical Chemistry	wikipedia.org
Heat Capacity at Constant Pressure	`C_P = (∂H/∂T)_P`	Physical Chemistry, Thermodynamics	wikipedia.org
Heat Capacity at Constant Volume	`C_V = (∂U/∂T)_V`	Physical Chemistry, Thermodynamics	wikipedia.org
Mayer’s Relation (ideal gas)	`C_P − C_V = R`	Physical Chemistry, Thermodynamics	wikipedia.org
Reversible Adiabatic Relation	`P V^γ = constant`	Physical Chemistry, Thermodynamics	wikipedia.org
Reversible Adiabatic Temperature–Volume Relation	`T V^(γ−1) = constant`	Physical Chemistry, Thermodynamics	wikipedia.org
Reversible Adiabatic Temperature–Pressure Relation	`T P^((1−γ)/γ) = constant`	Physical Chemistry, Thermodynamics	wikipedia.org
Joule–Thomson Coefficient	`μ_JT = (∂T/∂P)_H`	Physical Chemistry, Thermodynamics	wikipedia.org
Clapeyron Equation	`dP/dT = ΔS / ΔV = ΔH / (T ΔV)`	Physical Chemistry, Thermodynamics, Inorganic Chemistry	wikipedia.org
Clausius–Clapeyron Equation	`ln(P_2/P_1) = −ΔH_phase/R (1/T_2 − 1/T_1)`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
Gibbs Phase Rule	`F = C − P + 2`	Physical Chemistry, Thermodynamics, Inorganic Chemistry	wikipedia.org
Chemical Potential	`μ_i = (∂G/∂n_i)_(T,P,n_j)`	Physical Chemistry, Thermodynamics	wikipedia.org
Chemical Potential from Activity	`μ_i = μ_i° + R T ln a_i`	Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Gibbs–Duhem Equation	`Σn_i dμ_i = −S dT + V dP`	Physical Chemistry, Thermodynamics	wikipedia.org
Partial Molar Quantity	`M̄_i = (∂M/∂n_i)_(T,P,n_j)`	Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Activity (mole-fraction convention)	`a_i = γ_i x_i`	Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Activity (concentration convention)	`a_i = γ_i c_i / c°`	Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Ionic Strength	`I = (1/2) Σ c_i z_i^2`	Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Debye–Hückel Limiting Law	`log γ_i = −A z_i^2 √I`	Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Extended Debye–Hückel Equation	`log γ_i = −A z_i^2 √I / (1 + B a_i √I)`	Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Raoult’s Law	`P_i = x_i P_i°`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Henry’s Law	`C = k_H P`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Osmotic Pressure	`π = i M R T`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Boiling-Point Elevation	`ΔT_b = i K_b m`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Freezing-Point Depression	`ΔT_f = i K_f m`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
van ’t Hoff Factor	`i = observed colligative property / calculated nonelectrolyte value`	General Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Langmuir Adsorption Isotherm	`θ = K P / (1 + K P)`	Physical Chemistry, Thermodynamics, Inorganic Chemistry	wikipedia.org
Freundlich Adsorption Isotherm	`x/m = K P^(1/n)`	Physical Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
Equilibrium Constant (concentration form)	`K_c = Π[products]^ν / Π[reactants]^ν`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Equilibrium Constant (pressure form)	`K_p = Π(P_products)^ν / Π(P_reactants)^ν`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Kp–Kc Relation	`K_p = K_c (R T)^Δn_gas`	General Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Reaction Quotient	`Q = Πa_products^ν / Πa_reactants^ν`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
van ’t Hoff Equation	`ln(K_2/K_1) = −ΔH°/R (1/T_2 − 1/T_1)`	Physical Chemistry, Thermodynamics, General Chemistry	wikipedia.org
pH Definition	`pH = −log[H_3O^+]`	General Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
pOH Definition	`pOH = −log[OH^−]`	General Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
pKw Relation	`pH + pOH = pK_w`	General Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Water Ion Product	`K_w = [H_3O^+][OH^−]`	General Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Acid Dissociation Constant	`K_a = [H_3O^+][A^−] / [H A]`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Base Dissociation Constant	`K_b = [H B^+][OH^−] / [B]`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
pKa Definition	`pK_a = −log K_a`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
pKb Definition	`pK_b = −log K_b`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Henderson–Hasselbalch Equation (acid buffer)	`pH = pK_a + log([A^−]/[H A])`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Henderson–Hasselbalch Equation (base buffer)	`pOH = pK_b + log([H B^+]/[B])`	General Chemistry, Analytical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Solubility Product	`K_sp = Π[ion]^ν`	General Chemistry, Analytical Chemistry, Inorganic Chemistry, Physical Chemistry	wikipedia.org
Weak Acid Approximation	`[H_3O^+] ≈ √(K_a C_a)`	General Chemistry, Analytical Chemistry	libretexts.org
Weak Base Approximation	`[OH^−] ≈ √(K_b C_b)`	General Chemistry, Analytical Chemistry	libretexts.org
Amphiprotic Salt Approximation	`pH ≈ (1/2)(pK_a1 + pK_a2)`	General Chemistry, Analytical Chemistry	libretexts.org
Ostwald’s Dilution Law	`K_a = c α^2 / (1 − α)`	Physical Chemistry, General Chemistry, Analytical Chemistry	wikipedia.org
Degree of Dissociation	`α = amount dissociated / initial amount`	General Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Buffer Capacity	`β = d n_strong base(or acid) / d(pH)`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Distribution Law (Nernst)	`K_D = C_1 / C_2`	Analytical Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Differential Rate Law	`rate = k [A]^m [B]^n`	General Chemistry, Physical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Overall Reaction Order	`n = m + n + ...`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Integrated Zero-Order Rate Law	`[A]_t = [A]_0 − k t`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Integrated First-Order Rate Law	`ln[A]_t = ln[A]_0 − k t`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Integrated Second-Order Rate Law	`1/[A]_t = 1/[A]_0 + k t`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Zero-Order Half-Life	`t_1/2 = [A]_0 / (2 k)`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
First-Order Half-Life	`t_1/2 = ln 2 / k`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Second-Order Half-Life	`t_1/2 = 1 / (k [A]_0)`	General Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Arrhenius Equation	`k = A e^(−E_a / R T)`	General Chemistry, Physical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Linearized Arrhenius Equation	`ln k = ln A − E_a/(R T)`	Physical Chemistry, Organic Chemistry, General Chemistry	wikipedia.org
Eyring Equation	`k = (κ k_B T / h) e^(−ΔG‡ / R T)`	Physical Chemistry, Organic Chemistry, Thermodynamics	wikipedia.org
Nernst Equation	`E = E° − (R T / n F) ln Q`	General Chemistry, Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Nernst Equation at 25 °C	`E = E° − (0.05916/n) log Q`	General Chemistry, Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Standard Cell Potential	`E°_cell = E°_cathode − E°_anode`	General Chemistry, Analytical Chemistry, Inorganic Chemistry	wikipedia.org
Electrochemical Free Energy	`ΔG = −n F E`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Standard Electrochemical Free Energy	`ΔG° = −n F E°`	General Chemistry, Physical Chemistry, Thermodynamics, Analytical Chemistry	wikipedia.org
Charge–Current–Time Relation	`Q = I t`	General Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Faraday’s First Law of Electrolysis	`m = Q M / (n F)`	General Chemistry, Analytical Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Moles of Electrons	`n_e = Q / F`	General Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Radioactive Decay Law	`N_t = N_0 e^(−λ t)`	General Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Radioactive Activity	`A = λ N`	General Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Radioactive Half-Life	`t_1/2 = ln 2 / λ`	General Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Planck Relation	`E = h ν`	General Chemistry, Physical Chemistry	wikipedia.org
Photon Energy–Wavelength Relation	`E = h c / λ`	General Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
de Broglie Relation	`λ = h / p`	General Chemistry, Physical Chemistry	wikipedia.org
Heisenberg Uncertainty Principle	`Δx Δp ≥ ħ/2`	General Chemistry, Physical Chemistry	wikipedia.org
Bohr Radius	`r_n = a_0 n^2 / Z`	General Chemistry, Physical Chemistry	wikipedia.org
Bohr Energy Levels	`E_n = −2.178×10^−18 J · Z^2 / n^2`	General Chemistry, Physical Chemistry	wikipedia.org
Rydberg Equation	`1/λ = R_H (1/n_1^2 − 1/n_2^2)`	General Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Coulomb’s Law	`F = k q_1 q_2 / r^2`	General Chemistry, Physical Chemistry, Inorganic Chemistry	wikipedia.org
Formal Charge	`FC = valence e^− − nonbonding e^− − (bonding e^− / 2)`	General Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Schrödinger Equation (time-independent)	`Ĥ ψ = E ψ`	Physical Chemistry	wikipedia.org
Wave Equation Form of Schrödinger Equation	`−(ħ^2/2m)∇^2ψ + Vψ = Eψ`	Physical Chemistry	wikipedia.org
Wavefunction Normalization	`∫ \|ψ\|^2 dτ = 1`	Physical Chemistry	wikipedia.org
Expectation Value	`⟨A⟩ = ∫ ψ* Â ψ dτ`	Physical Chemistry	wikipedia.org
Particle in a Box Energy	`E_n = n^2 h^2 / (8 m L^2)`	Physical Chemistry	wikipedia.org
Harmonic Oscillator Energy	`E_v = (v + 1/2) h ν`	Physical Chemistry, Analytical Chemistry	wikipedia.org
Rigid Rotor Energy	`E_J = J(J+1) ħ^2 / (2 I)`	Physical Chemistry, Analytical Chemistry	wikipedia.org
Rotational Constant	`B = h / (8 π^2 I c)`	Physical Chemistry, Analytical Chemistry	wikipedia.org
Boltzmann Distribution	`N_j / N_i = (g_j/g_i) e^(−ΔE / k_B T)`	Physical Chemistry, Analytical Chemistry, Thermodynamics	wikipedia.org
Partition Function	`q = Σ g_i e^(−ε_i / k_B T)`	Physical Chemistry, Thermodynamics	wikipedia.org
Beer–Lambert Law	`A = ε b c`	Analytical Chemistry, General Chemistry, Physical Chemistry, Organic Chemistry, Inorganic Chemistry	wikipedia.org
Absorbance Definition	`A = −log T = log(I_0 / I)`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Transmittance Definition	`T = I / I_0`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Wavenumber	`ṽ = 1 / λ`	Analytical Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Hooke’s Law Approximation for IR Stretching	`ṽ = (1 / 2πc) √(k / μ)`	Organic Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Reduced Mass	`μ = m_1 m_2 / (m_1 + m_2)`	Organic Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
NMR Chemical Shift	`δ = ((ν_sample − ν_ref) / ν_0) × 10^6`	Organic Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Bragg’s Law	`n λ = 2 d sin θ`	Inorganic Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Scherrer Equation	`D = K λ / (β cos θ)`	Inorganic Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Cubic Lattice d-Spacing	`d_hkl = a / √(h^2 + k^2 + l^2)`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Unit Cell Density	`ρ = Z M / (N_A a^3)`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Madelung/Born–Landé Lattice Energy	`U = −(N_A M z^+ z^− e^2 / 4π ε_0 r_0)(1 − 1/n)`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Kapustinskii Equation	`U = K ν \|z^+ z^−\| / r_0 · (1 − d/r_0)`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Born Solvation Equation	`ΔG_solv = −(N_A z^2 e^2 / 8π ε_0 r)(1 − 1/ε)`	Inorganic Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Crystal Field Stabilization Energy (octahedral)	`CFSE_oct = (−0.4 n_t2g + 0.6 n_eg) Δ_o`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Crystal Field Stabilization Energy (tetrahedral)	`CFSE_tet = (−0.6 n_e + 0.4 n_t2) Δ_t`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Tetrahedral–Octahedral Splitting Relation	`Δ_t ≈ (4/9) Δ_o`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Spin-Only Magnetic Moment	`μ_eff = √(n(n+2)) μ_B`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Magnetic Moment from Susceptibility	`μ_eff = 2.828 √(χ_M T)`	Inorganic Chemistry, Physical Chemistry, Analytical Chemistry	wikipedia.org
Curie Law	`χ = C / T`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Curie–Weiss Law	`χ = C / (T − θ)`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Effective Atomic Number	`EAN = Z − oxidation state + electrons donated by ligands`	Inorganic Chemistry	wikipedia.org
Slater’s Rule / Effective Nuclear Charge	`Z_eff = Z − S`	General Chemistry, Inorganic Chemistry, Physical Chemistry	wikipedia.org
Goldschmidt Tolerance Factor	`t = (r_A + r_O) / (√2 (r_B + r_O))`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Bond Valence Equation	`s = exp[(R_0 − R)/B]`	Inorganic Chemistry, Physical Chemistry	wikipedia.org
Degree of Unsaturation (DBE / IHD)	`DBE = C − H/2 − X/2 + N/2 + 1`	Organic Chemistry, General Chemistry	wikipedia.org
Enantiomeric Excess	`ee = \|R − S\| / (R + S) × 100`	Organic Chemistry, Analytical Chemistry	wikipedia.org
Optical Purity	`optical purity = (observed rotation / rotation of pure enantiomer) × 100`	Organic Chemistry, Analytical Chemistry	wikipedia.org
Specific Rotation	`[α]^T_λ = α_obs / (l c)`	Organic Chemistry, Analytical Chemistry	wikipedia.org
Hückel’s Rule	`π electrons = 4n + 2`	Organic Chemistry, Physical Chemistry	wikipedia.org
Hammett Equation (equilibrium form)	`log(K/K_0) = ρ σ`	Organic Chemistry, Physical Chemistry	wikipedia.org
Hammett Equation (rate form)	`log(k/k_0) = ρ σ`	Organic Chemistry, Physical Chemistry	wikipedia.org
Taft Equation	`log(k_s/k_CH3) = ρσ + δE_s`	Organic Chemistry, Physical Chemistry	wikipedia.org
Partition Coefficient	`P = [solute]_octanol / [solute]_water`	Organic Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
logP	`logP = log10([solute]_octanol / [solute]_water)`	Organic Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
NMR n+1 Rule	`multiplicity = n + 1`	Organic Chemistry, Analytical Chemistry	libretexts.org
Index of Refraction (Snell / refractometry)	`n_1 sinθ_1 = n_2 sinθ_2`	Organic Chemistry, Analytical Chemistry, Physical Chemistry	wikipedia.org
Eyring–Polanyi Linear Form	`ln(k/T) = −ΔH‡/(R T) + ln(k_B/h) + ΔS‡/R`	Organic Chemistry, Physical Chemistry, Thermodynamics	wikipedia.org
Calibration Curve	`y = m x + b`	Analytical Chemistry	wikipedia.org
Mean	`x̄ = Σx_i / n`	Analytical Chemistry	wikipedia.org
Variance	`s^2 = Σ(x_i − x̄)^2 / (n − 1)`	Analytical Chemistry	wikipedia.org
Standard Deviation	`s = √(Σ(x_i − x̄)^2 / (n − 1))`	Analytical Chemistry	wikipedia.org
Standard Error of the Mean	`s_x̄ = s / √n`	Analytical Chemistry	wikipedia.org
Confidence Interval	`x̄ ± t s/√n`	Analytical Chemistry	wikipedia.org
Relative Standard Deviation	`%RSD = (s / x̄) × 100`	Analytical Chemistry	wikipedia.org
Limit of Detection	`LOD = 3 σ / m`	Analytical Chemistry	wikipedia.org
Limit of Quantitation	`LOQ = 10 σ / m`	Analytical Chemistry	wikipedia.org
Titration Stoichiometry	`C_a V_a / ν_a = C_b V_b / ν_b`	Analytical Chemistry, General Chemistry, Inorganic Chemistry	wikipedia.org
Moles at Equivalence	`n_a / ν_a = n_b / ν_b`	Analytical Chemistry, General Chemistry	wikipedia.org
Recovery Percentage	`% recovery = (measured / added) × 100`	Analytical Chemistry	wikipedia.org
Distribution Ratio	`D = total analyte concentration in phase 1 / total analyte concentration in phase 2`	Analytical Chemistry, Physical Chemistry, Organic Chemistry	wikipedia.org
Chromatographic Retention Factor	`k' = (t_R − t_M) / t_M`	Analytical Chemistry	wikipedia.org
Chromatographic Selectivity	`α = k'_2 / k'_1`	Analytical Chemistry	wikipedia.org
Chromatographic Resolution	`R_s = 2(t_R2 − t_R1) / (w_1 + w_2)`	Analytical Chemistry	wikipedia.org
Theoretical Plate Number	`N = 16(t_R / w)^2`	Analytical Chemistry	wikipedia.org
Theoretical Plate Number (half-height form)	`N = 5.54(t_R / w_1/2)^2`	Analytical Chemistry	wikipedia.org
Plate Height	`H = L / N`	Analytical Chemistry	wikipedia.org
Conductance	`G = 1 / R`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Conductivity	`κ = G l / A`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Molar Conductivity	`Λ_m = κ / c`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Kohlrausch’s Law	`Λ_m = Λ_m° − K √c`	Analytical Chemistry, Physical Chemistry	wikipedia.org
Coulometric Relation	`Q = n F N`	Analytical Chemistry, Physical Chemistry	libretexts.org
Randles–Sevcik Equation	`i_p = 2.69×10^5 n^(3/2) A D^(1/2) C ν^(1/2)`	Analytical Chemistry, Physical Chemistry	wikipedia.org

Chemistry Formulas

Chemistry Formula Compendium

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