Rhodium

Rhodium, ₄₅Rh

Rhodium
Pronunciation	/ˈroʊdiəm/ ​(ROH-dee-əm)
Appearance	silvery white metallic
Standard atomic weight Ar, std(Rh)	7002102905490000000♠102.90549(2)
Mass number	Rh:
Rhodium in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium Co ↑ Rh ↓ Ir ruthenium ← rhodium → palladium
Atomic nummer (Z)	45
Group	group 9
Period	period 5
Block	d-block
Element category	Transeetion metal
Electron confeeguration	[Kr] 4d8 5s1
Electrons per shell	2, 8, 18, 16, 1
Pheesical properties
Phase at STP	solit
Meltin pynt	2237 K ​(1964 °C, ​3567 °F)
Bylin pynt	3968 K ​(3695 °C, ​6683 °F)
Density (near r.t.)	12.41 g/cm3
when liquid (at m.p.)	10.7 g/cm3
Heat o fusion	26.59 kJ/mol
Heat o vapourisation	494 kJ/mol
Molar heat capacity	24.98 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 2288 2496 2749 3063 3405 3997
Atomic properties
Oxidation states	−3, −1, 0, +1, +2, +3, +4, +5, +6 (an amphoteric oxide)
Electronegativity	Pauling scale: 2.28
Atomic radius	empirical: 134 pm
Covalent radius	142±7 pm
Spectral lines o rhodium
Ither properties
Naitural occurrence	Rh: Primordial
Creestal structur	​face-centred cubic (fcc)
Speed o soond thin rod	4700 m/s (at 20 °C)
Thermal expansion	8.2 µm/(m·K) (at 25 °C)
Thermal conductivity	150 W/(m·K)
Electrical resistivity	43.3 n Ω·m (at 0 °C)
Magnetic orderin	paramagnetic
Young's modulus	380 GPa
Shear modulus	150 GPa
Bulk modulus	275 GPa
Poisson ratio	0.26
Mohs haurdness	6.0
Vickers haurdness	1246 MPa
Brinell haurdness	1100 MPa
CAS Nummer	7440-16-6
History
Diskivery	William Hyde Wollaston (1804)
First isolation	William Hyde Wollaston (1804)
Main isotopes o rhodium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 99Rh syn 16.1 d ε 99Ru γ - 101mRh syn 4.34 d ε 101Ru IT 101Rh γ - 101Rh syn 3.3 y ε 101Ru γ - 102mRh syn 2.9 y ε 102Ru γ - 102Rh syn 207 d ε 102Ru β+ 102Ru β− 102Pd γ - 103Rh 100% - (SF) 105Rh syn 35.36 h β− 105Pd γ -
Decay modes in parentheses are predictit, but hae nae yet been observed

Rhodium is a chemical element that is a rare, sillery-white, haird, an chemically inert transeetion metal an a member o the platinum group. It haes the chemical seembol Rh an atomic nummer 45. It is componed o anly ane naiturally-occurrin isotope, ¹⁰³Rh. Naiturally occurrin rhodium is uisually foond as the free metal, alloyed wi seemilar metals, an rarely as a chemical compoond in minerals sic as bowieite an rhodplumsite. It is ane o the rarest an maist valuable precious metals.