Arsenic (As) VS Phosphorus (P)
A definitive side-by-side comparison of two essential element profiles.
VS
Main Differences
Arsenic (As) is an element in the metalloids category with an atomic number of 33. Phosphorus (P) is an element in the nonmetals category with an atomic number of 15.
Arsenic (As) is 3.1x denser than Phosphorus (P). Furthermore, Arsenic (As) melts at a significantly higher temperature than Phosphorus (P) (a difference of 772.7 Kelvin).
Where do the names come from?
Arsenic (As) Naming History
The name Arsenic is thought to come from 'arsenikon', the Greek name for the yellow pigment orpiment.
Phosphorus (P) Naming History
The name Phosphorus is derived from the Greek 'phosphoros', meaning bringer of light.
Related Comparisons
Compare
Arsenic (As)
Phosphorus (P)
Category
Metalloids
Nonmetals
Atomic Number
33
15
Symbol
As
P
Atomic Mass
74.922 u
30.974 u
Group
15
15
Period
4
3
Block
p-block
p-block
Standard State (at 20°C)
solid
solid
Density
5.727 g/cm³
1.823 g/cm³
Melting Point (°C)
Sublimes at 616°C
44.15°C
Melting Point (°F)
1141°F
111.47°F
Melting Point (K)
1090 (sublimes) K
317.3 K
Boiling Point (°C)
Sublimes at 616°C
280.5°C
Boiling Point (°F)
1141°F
536.9°F
Boiling Point (K)
887 (sublimes) K
553.7 K
Year Discovered:
1250
1669
CAS Number
7440-38-2
7723-14-0
Origin of Name:
The name is thought to come from 'arsenikon', the Greek name for the yellow pigment orpiment.
The name is derived from the Greek 'phosphoros', meaning bringer of light.