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SI and Derived Units

SI units

Unit

Symbol

Physical Quantity

Base units

ampere

A

electric current

candela

cd

luminous intensity

kelvin

K

thermodynamic temperature

kilogram

kg

mass

meter

m

length

mole

mol

amount of substance

second

s

time

Supplementary units

radian

rad

plane angle

steradian

sr

solid angle

From The ACS Style Guide (J. S. Dodd, editor, 1986) 

Prefix multipliers

Factor

Prefix

Symbol

1018

atto

a

1015

femto

f

1012

pico

p

109

nano

n

106

micro

μ

103

milli

m

102

centi

c

101

deci

d

101

deka

da

102

hecto

h

103

kilo

k

106

mega

M

109

giga

G

1012

tera

T

1015

peta

P

1018

exa

E

From The ACS Style Guide (J. S. Dodd, editor, 1986)

SI-derived units

Unit Symbol Quantity Equivalent Common Usage SI Base Unit Derivation 

becquerel

Bq

activity (of a radionuclide)

s1

coulomb

C

quantity of electricity, electric charge

As, sA

farad

F

capacitance

C/V

m2kg1s4A2

gray

Gy

absorbed dose, kerma, specific energy imparted

J/kg

m2/s2

henry

H

inductance

Wb/A

m2kgs2A2

hertz

Hz

frequency

s1

joule

J

energy, work, quantity of heat

Nm

m2kgs2

lumen

lm

luminous flux

lm

cdsr

lux

lx

illuminance

lm/m2

m2cdsr

newton

N

force

mkgs2

ohm

Ω

electrical resistance

V/A

m2kgs3A2

pascal

Pa

pressure, stress

N/m2

m1kgs2

siemens

S

conductance

A/V

m2kg1s3A2

sievert

Sv

dose equivalent

J/kg

m2/s2

tesla

T

magnetic flux density

Wb/m2

kgs2A1

volt

V

electric potential, potential difference, electromotive force

W/A

m2kgs3A1

watt

W

power, radiant flux

J/s

m2kgs3

weber Wb magnetic flux Vs m2kgs2A1

From The ACS Style Guide (J. S. Dodd, editor, 1986) 

SI-derived compound units

Unit

Symbol

Quantity

In Terms of Other Units

ampere per meter

A/m

magnetic field strength

ampere per square meter

A/m2

current density

candela per square meter

cd/m2

luminance

coulomb per cubic meter

C/m3

electric charge density

m3sA

coulomb per kilogram

C/kg

exposure (X-ray, gamma ray)

coulomb per square meter

C/m2

electric flux density

m2sA

cubic meter

m3

volume

cubic meter per kilogram

m3/kg

specific volume

farad per meter

F/m

permittivity

m3kg1s4A2

henry per meter

H/m

permeability

mkgs2A2

joule per cubic meter

J/m3

energy density

m1kgs2

joule per kelvin

J/K

heat capacity, entropy

m2kgs2K1

joule per kilogram

J/kg

specific energy

m2/s2

joule per kilogram kelvin

J/(kgK)

specific heat capacity, specific entropy

m2s2K1

joule per mole 

J/mol

molar energy

m2kgs2mol1

joule per mole kelvin

J/(molK)

molar entropy, molar heat capacity

m2kgs2K1mol1

kilogram per cubic meter

kg/m3

density, mass density

meter per second

m/s

speed, velocity

meter per square second

m/s2

acceleration

mole per cubic meter

mol/m3

concentration (amount of substance per unit volume)

newton meter

Nm

moment of force

m2kgs2

newton per meter

N/m

surface tension

kg/s2

pascal second

Pas

dynamic viscosity

m1kgs1

radian per second

rad/s

angular velocity

radian per square second

rad/s2

angular acceleration

reciprocal meter

m1

wavenumber

reciprocal second

s1

frequency

square meter

m2

area

square meter per second

m2/s

kinematic viscosity

volt per meter

V/m

electric field strength

mkgs3A1

watt per meter kelvin

W/(mK)

thermal conductivity

mkgs3K1

watt per square meter

W/m2

heat flux density, irradiance

kg/s3

watt per square meter steradian

W/(m2sr)

radiance

watt per steradian

W/sr

radiant intensity

From The ACS Style Guide (J. S. Dodd, editor, 1986)

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last edited 07/29/03