III refers to the boron group (the table columns). V refers to the nitrogen group (the table rows).

III-V compounds (binary) 5
B 		13
Al 		31
Ga 		49
In 		   81   
Tl
7
N 		BN AlN GaN InN TlN
15
P 		BP AlP GaP InP TlP
33
As 		BAs AlAs GaAs InAs TlAs
51
Sb 		BSb AlSb GaSb InSb TlSb
83
Bi 		BBi AlBi GaBi InBi TlBi
Key: Polyatomic nonmetals Diatomic nonmetals Metalloids Post-​transition metals Atomic number in black above element
Category