Group 9, numbered by IUPAC nomenclature, is a group of chemical element in the periodic table. Members are cobalt (Co), rhodium (Rh), iridium (Ir) and perhaps also the chemically uncharacterized meitnerium (Mt). These are all transition metals in the d-block. All known isotopes of meitnerium are radioactive with short half-lives, and it is not known to occur in nature; only minute quantities have been synthesized in laboratories.
Like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior; however, rhodium deviates from the pattern.
|Group 9 in the periodic table|
27 Transition metal
45 Transition metal
77 Transition metal
109 unknown chemical properties
|Z||Element||No. of electrons/shell|
|27||cobalt||2, 8, 15, 2|
|45||rhodium||2, 8, 18, 16, 1|
|77||iridium||2, 8, 18, 32, 15, 2|
|109||meitnerium||2, 8, 18, 32, 32, 15, 2 (predicted)|
Meitnerium has not been isolated in pure form, and its properties have not been conclusively observed; only cobalt, rhodium, and iridium have had their properties experimentally confirmed. All three elements are typical silvery-white transition metals, hard, and have high melting and boiling points.
Cobalt has been discovered in Egyptian and Persian artifacts from before the 2nd millennium BCE. Rhodium was discovered in 1803 when William Hyde Wojopllaston dissolved platinum ore in aqua regia, then neutralized the acid with sodium hydroxide. Wollaston then added ammonium chloride, and dissolved all metals except rhodium and palladium with the nitric acid in the aqua regia. Iridium was discovered in a very similar way in 1804 by Smithson Tennant. Meitnerium was discovered in 1982 by bombarding bismuth-209 with iron-58.
All group 9 elements are relatively rare in the earth's crust, with the most abundant, cobalt, only accounting for 0.0029% of the Earth's crust. Rhodium and iridium are two of the rarest naturally occurring elements in the earth, only found in platinum ores. Meitnerium has only been produced in nuclear reactors and has never been observed in nature nor isolated in pure form.
Cobalt is an essential trace nutrient to all animals, found in vitamin B-12. Rhodium, iridium, and meitnerium have no known biological roles.
G9, G.IX, G09 or G-9 has several uses including:
Group of Nine, a group of nine European states
G9 (consortium), a name for a group of nine Australian internet providers
G9 (album), the debut album of Gloc-9v
G9, a bipin lamp standard
G9 star, a subclass of G-class stars
Canon PowerShot G9, a digital camera
County Route G9 (California)
Gotha G.IX, a 1918 German bomber aircraft
HMS G9, a British G class submarine and one of eight British submarines lost to "friendly fire" in World War I
HMS Quilliam (G09), a 1941 British Royal Navy Q class destroyer
G9, in internet slang, means "Good night"and also :n
Air Arabia, IATA airline designator
Gaia Online, donation item
Gol Transportes Aéreos (Brazil), IATA airline designator
Group 9 element of the periodic tabled
G09, Sequelae of inflammatory diseases of central nervous system ICD-10 code
Nachtjagdgeschwader 1, from its historic Geschwaderkennung code with the Luftwaffe in World War IIGroup 9
Group 9 may refer to:
Group 9 element
Group 9 Rugby LeagueIndex of chemistry articles
Chemistry (from Egyptian kēme (chem), meaning "earth") is the physical science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions.Below is a list of chemistry-related articles. Chemical compounds are listed separately at list of organic compounds, list of inorganic compounds or list of biomolecules.
|Periodic table forms|
|Sets of elements|
Group 9 elements