Periodic Table ~ phosphorus ~ Element ~ CAS 7723-14-0

phosphorus

Name	phosphorus
Symbol	P
Atomic Weight	30.973761
Atomic Number	15
CAS ID	7723-14-0
Group Number	15
Group Name	Pnictogen
Period Number	3
Origin of Name	Greek, phosphoros = "bringer of light."
Year Discovered	1669
Discovery Credits	Discovered by Hennig Brandt at Hamburg, Germany
Class	Non-Metallic
Color	Red or Silvery White
Standard State	Solid at 77 F & 298 K
Description	White phosphorus (P4) is soft and flammable, red phosphorus is powdery and usually non-flammable. Neither form reacts with water or dilute acid but alkalis react to form phosphine gas. Used in fertilizers, insecticides, metal treatment, detergents, etc Diagnostic tests: Compounds containing phosphates (PO₄^3-) give a green flame test, especially after being moistened with sulfuric acid (H₂SO₄) although this test may be rendered unsatisfactory due to other coloring agents. If a powdered sample is fused in a closed tube with metallic sodium or magnesium and afterward moistened with water, hydrogen phosphide is given off, recognized by its disagreeable odor.