One of the differences between metals and dielectrics is the presence of 'conduction electrons', which form an electron gas and participate in thermal motion. These electrons are held inside the metal, so there are forces near the surface that act on the electrons and are directed into the metal. For the electron to be able to leave the metal beyond its limits, a certain work W must be done against these forces, which is called the work function of the electron from the metal.

The following table lists the work function of electrons related to polycrystalline samples, the surface of which is vacuum cleaned by calcination or mechanical treatment. Insufficiently reliable data are enclosed in parentheses.

Element	Formula	Electron work function ( W , eV)
silver	Ag	4,7
aluminum	Al	4,2
arsenic	As	4.79 - 5.11
gold	Au	4,8
boron	B	(4,60)
barium	Ba	2.52
beryllium	Be	3.92
bismuth	Bi	4.34
carbon (graphite)	C	4.45 - 4.81
calcium	Ca	2.76 - 3.20
cadmium	Cd	4.04
cerium	Ce	2.6 - 2.88
cobalt	Co	4.40
chrome	Cr	4.60
cesium	Cs	1.94
copper	Cu	4.36
iron	Fe	4.40 - 4.71
gallium	Ga	3.96 - 4.16
germanium	Ge	4.66
hafnium	Hf	(3, 53)
mercury	Hg	4,52
indium	In	(3.60 - 4.09)
iridium	Ir	(4,57)
potassium	K	2.25
lanthanum	La	(3,3)
lithium	Li	2,49
magnesium	Mg	3.67
manganese	Mn	3, 76 - 3.95
molybdenum	Mo	4.20
sodium	Na	2,28
niobium	Nb	3.99
neodymium	Nd	(3,3)
nickel	Ni	4.91 - 5.01
osmium	Os	(4,55)
lead	Pb	4.05
palladium	Pd	(4 , 98)
praseodymium	Pr	(2,7)
platinum	Pt	5.30 - 5.55
rubidium	Rb	2.13
rhenium	Re	4.98
rhodium	Rh	4.75
ruthenium	Ru	(4,52)
antimony	Sb	4.08 - 4,56
scandium	Sc	(3.2 - 3.33)
selenium	Se	4.86
silicon	Si	3,59 - 4.67
samarium	Sm	(3,2)
tin (γ -form)	Sn	4,38
tin (β -form)	Sn	4 , 50
strontium	Sr	2.74
tantalum	Ta	4.13
tellurium	Te	4.73
thorium	Th	3.35 - 3.47
titanium	Ti	4.14 - 4.50
thallium	Tl	3.68 - 4.05
uranium	U	3.27 - 4.32
vanadium	V	3.77 - 4.44
tungsten	W	4,54
zinc	Zn	4.22 - 4.27
zirconium	Zr	3.96 - 4.16

The following table shows the values of the work function of electrons related to polycrystalline samples, the surface of which is vacuum cleaned by calcination or mechanical treatment. Insufficiently reliable data are enclosed in parentheses.

Substance	Formula	Electron work function ( W , eV)
silver bromide	AgBr	~ 3.9
silver chloride	AgCl	~ 4,6
silver iodide	AgI	~ 4,0
silver sulfide	Ag 2 S	~ 3, 8
boron trioxide	B 2 O 3	4,7
barium oxide	BaO	1,0 - 1,6
tungsten barium	BaWO 4	2,27
beryllium oxide	BeO	3.8 - 4.7
calcium oxide	CaO	1,8 - 2,4
orthotungstate calcium	Ca 3 WO 6	2 , 13
chromium boride	CrB 2	3.36
cesium oxide	Cs 2 O	1.0 - 1.17
copper oxide	CuO	4.35 - 5.34
copper oxide	Cu 2 O	5,15
iron oxide	FeO	3.85
water	H 2 O	6,1
hafnium carbide	HfC	2,04
magnesium oxide	MgO	3.1 - 4.4
manganese diboride	MnB 2	4,14
molybdenum diboride	MoB 2	3, 38
molybdenum trioxide	MoO 3	4,25
molybdenum silicide	MoSi 2	5.0 - 6.0
sodium chloride	NaCl	4,2
niobium boride	NbB 2	3.65
niobium carbide	NbC	2.24
nickel oxide	NiO	5,55
scandium boride	ScB 2	2.3 - 2.9
silica	SiO 2	5,0
strontium oxide	SrO	2,0 - 2 , 6
tantalum carbide	TaC	3.05 - 3.14
tantalum pentoxide	Ta2O5	4.65
thorium dicarbide	ThC 2	3,5
thorium oxide	ThO 2	2.54 - 2.67
sultitanium feed	TiS	3,4
titanium diboride	TiB 2	3.88 - 3.95
titanium carbide	TiC	2.35 - 3.35
titanium nitride	TiN	2.92
titanium oxide	TiO	2.96 - 3.1
titanium dioxide	TiO 2	4,7
uranium carbide	UC	2.9 - 4.6
vanadium diboride	V B 2	3.88 - 3.95
tungsten diboride	WB 2	2.62
tungsten dioxide	WO 2	4.96
tungsten disilicide	WSi 2	5,0 - 6,0
zirconium boride	ZrB	4.48
zirconium diboride	ZrB 2	3.70
zirconium carbide	ZrC	2,2 - 3, 8
Zirconium nitride	ZrN	2.92