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Commonly used symbols in Scientific Writing
Chemical Reactions
| Name |
Symbol |
| affinity (-ΣνBμB) of a reaction |
A |
| collision number (collisions per unit volume and unit time) |
Z |
| degree of reaction (e.g., degree of dissociation) |
α |
| equilibrium constant |
K |
| equilibrium quotient or equilibrium product (of molarities) |
Q |
| extent of reaction (dnB = νBdξ)
| ξ |
| rate constant |
k |
| rate constant corresponding to the rate Z |
z |
| rate of reaction |
ν, r, s, J |
| standard equation of chemical reaction |
ΣνBB=0 |
| stoichiometric number of molecules (negative for reactants, positive for products) |
ν |
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Electricity and Magnetism
| Name |
Symbol |
| admittance |
Y |
| capacitance |
C |
| charge density |
ρ |
| dielectric polarization |
P |
| dipole moment |
μ |
| electric current |
I, i |
| electric current density |
J |
| electric displacement |
D |
| electric field strength |
E |
| electric polarizability of a molecule |
α, Y |
| electric potential |
V |
| electrokinetic potential |
ζ |
| elementary charge |
e |
| impedance |
Z |
| magnetic field strength |
H |
| magnetic induction |
B |
| magnetic permeability |
μ |
| magnetic susceptibility |
χ |
| magnetization |
M |
| mutual inductance |
M, L12 |
| permittivity (dielectric constant) |
ε |
| quantity of electricity |
Q |
| reactance |
X |
| resistance |
R |
| resistivity |
ρ |
| self inductance |
L |
| surface charge density |
σ |
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Electrochemistry
| Name |
Symbol |
| charge number of an ion, plus or minus |
z |
| degree of electrolytic dissociation |
α |
| electrolytic conductivity (specific conductance) |
κ |
| electromotive force |
E |
| equivalent or molar conductance of electrolyte or ion |
Λ |
| transport number |
t, T |
| Faraday's constant (the faraday) |
F |
| ionic strength |
I, μ |
| over potential |
η |
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Light
| Name |
Symbol |
| absorbance (extinction) [A=log (1/T)] |
A, E |
| absorption (extinction) coefficient [κlc = ln(1/T)] |
κ |
| absorption factor (fraction of incident radiant power which is absorbed) |
α |
| absorptivity (specific absorbance) [decadic absorption or extinction coefficient) |
a |
| angle of optical rotation |
α |
| illumination (dΦ/dS) |
E |
| luminance |
L, B |
| luminous emittance |
H |
| luminous intensity (dφ/dω) |
I |
| molar absorptivity (molar decadic absorption or extinction coefficient) [εlc = A] |
ε |
| Planck's constant |
h |
| Planck's constant divided by 2π |
ħ |
| quantity of light |
Q |
| radiant power, flux of light (dQ/dt) |
Φ |
| reflection factor (fraction of incident radiant power which is reflected) |
ρ |
| refraction index |
n |
| refractivity |
r |
| transmission factor (fraction of incident radiant power which is transmitted) |
τ |
| transmittance (T=I/IO) |
T |
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Mechanical and Related Quantities
| Name |
Symbol |
| angle of contact |
θ |
| compressibility |
κ |
| compression modulus (1/κ) |
K |
| fluidity |
φ |
| force |
F |
| force duce to gravity (weight) |
G, W |
| friction coefficient |
f |
| kinematic viscosity |
ν |
| modulus of elasticity |
E |
| moment of force |
M |
| power |
P |
| pressure |
p, P |
| shear modulus |
G |
| shear stress |
τ |
| surface tension |
γ, σ |
| traction |
σ |
| viscosity |
η |
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Molecular and Related Quantities
| Name |
Symbol |
| Avogadro's number |
N0 , L, N |
| characteristic temperature |
θ |
| concentration |
c |
| diameter of molecule |
σ, D |
| diffusion coefficient |
D |
| mean free path |
I |
| molality |
m |
| molar concentration of substance B |
cB , [B], c(B) |
| molar mass |
M |
| mole fraction |
x, X, y |
| molecular concentration |
C |
| molecular mass |
m |
| number of molecules |
N |
| number of moles |
n |
| osmotic pressure |
Π |
| partition function |
Q |
| statistical weight |
g, p |
| surface concentration |
Γ |
| symmetry number |
σ |
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Space, Time, Mass, and Related Quantites
| Name |
Symbol |
| acceleration |
a |
| acceleration of free fall |
g |
| angular frequency (2πν) |
ω |
| angular velocity |
ω |
| area |
A, S |
| density |
ρ |
| diameter |
d |
| frequency |
ν, f |
| height |
h |
| length |
l |
| mass |
m |
| moment of inertia |
I |
| path, length of arc |
s |
| period or other characteristic interval |
T, τ |
| plan angle |
α, β, γ, θ, φ, ψ |
| radius |
r |
| relative density |
d |
| solid angle |
ω |
| specific volume |
v |
| time |
t |
| velocity |
v, u, w |
| volume |
V, v |
| wave number |
σ, ν |
| wavelength |
λ |
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Thermodynamic and Related Quantities
| Name |
Symbol |
| activity coefficient |
f, γ |
| activity, absolute |
λ |
| activity, relative |
a |
| Boltzmann constant |
k |
| chemical potential |
μ |
| energy (Gibbs ε) |
E, U |
| enthalpy (Gibbs χ) |
H |
| entropy (Gibbs η) |
S |
| gas constant |
R |
| Gibbs function (ζ) |
G, F |
| heat |
q, Q |
| heat capacity |
C |
| Helmholtz free energy (Gibbs Ψ) |
A |
| Joule-Thomson coefficient |
μ |
| osmotic coefficient |
g, φ |
| ratio of specific heats cp/cv |
γ, κ |
| specific heat at constant pressure |
cp |
| specific heat at constant volume |
cv |
| temperature |
θ, t |
| temperature, absolute |
T |
| thermal conductivity |
γ |
| work |
w, A |
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