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Group →	9
↓ Period
4	27  Co
5	45  Rh
6	77  Ir
7	109  Mt

In modern IUPAC nomenclature, Group 9 of the periodic table contains the elements cobalt (Co), rhodium (Rh), iridium (Ir), and meitnerium (Mt). These are all d-block transition metals. All known isotopes of Mt 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 its electron configuration, especially the outermost shells resulting in trends in chemical behavior, though rhodium curiously does not follow the pattern:

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

[edit] Applications

• Alloys with other metals, primarially to add corrosion and wear resistance
• Industrial Catalysts
• Superalloys
• Electrical Components

[edit] See also

• Platinum group

Explanation of right side periodic table slice:

Transition metals

atomic number in black are solids

solid borders are older than the Earth (Primordial elements)

dashed borders have no isotopes older than the earth

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