Rhodium

Rhodium, ₄₅Rh

Rhodium
Pronunciation	/ˈroʊdiəm/ (listenⓘ) ​(ROH-dee-əm)
Appearance	silvery white metallic
Standard atomic weight Ar°(Rh)
	102.90549(2)[1]
Rhodium in the periodic table
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 Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver 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 Gold Mercury (element) Thallium Lead 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 Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Co ↑ Rh ↓ Ir ruthenium ← rhodium → palladium
Atomic number (Z)	45
Group	group 9
Period	period 5
Block	d-block
Electron configuration	[Kr] 4d8 5s1
Electrons per shell	2, 8, 18, 16, 1
Physical properties
Phase at STP	solid
Melting point	2237 K ​(1964 °C, ​3567 °F)
Boiling point	3968 K ​(3695 °C, ​6683 °F)
Density (near r.t.)	12.41 g/cm3
when liquid (at m.p.)	10.7 g/cm3
Heat of fusion	26.59 kJ/mol
Heat of vaporization	493 kJ/mol
Molar heat capacity	24.98 J/(mol·K)
Vapor pressure 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[2], −1, 0, +1,[3] +2, +3, +4, +5, +6, +7[4] (an amphoteric oxide)
Electronegativity	Pauling scale: 2.28
Ionization energies	1st: 719.7 kJ/mol 2nd: 1740 kJ/mol 3rd: 2997 kJ/mol
Atomic radius	empirical: 134 pm
Covalent radius	142±7 pm
Spectral lines of rhodium
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered cubic (fcc)
Speed of sound 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 nΩ⋅m (at 0 °C)
Magnetic ordering	paramagnetic[5]
Molar magnetic susceptibility	+111.0×10−6 cm3/mol (298 K)[6]
Young's modulus	380 GPa
Shear modulus	150 GPa
Bulk modulus	275 GPa
Poisson ratio	0.26
Mohs hardness	6.0
Vickers hardness	1100–8000 MPa
Brinell hardness	980–1350 MPa
CAS Number	7440-16-6
History
Discovery and first isolation	William Hyde Wollaston (1804)
Isotopes of rhodium v e
Main isotopes[7] Decay abun­dance half-life (t1/2) mode pro­duct 99Rh synth 16.1 d β+ 99Ru 101Rh synth 4.07 y ε 101Ru 101mRh synth 4.343 d ε 101Ru IT 101Rh 102Rh synth 207 d β+ 102Ru β− 102Pd 102mRh synth 3.742 y β+ 102Ru IT 102Rh 103Rh 100% stable 105Rh synth 35.341 h β− 105Pd
Category: Rhodium view talk edit | references

Rhodium is a chemical element. It has the chemical symbol Rh. It has the atomic number 45. It is a rare metal. It is silver white and hard. In chemistry it is placed in a group of metal elements named the transition metals. It is also part of the platinum group. Rhodium is found in platinum ores.

Rhodium is used as a catalyst in some platinum alloys. It is the most expensive precious metal.^[8]

1. ↑ "Standard Atomic Weights: Rhodium". CIAAW. 2017.
2. ↑ Ellis J E. Highly Reduced Metal Carbonyl Anions: Synthesis, Characterization, and Chemical Properties. Adv. Organomet. Chem, 1990, 31: 1-51.
3. ↑ "Rhodium: rhodium(I) fluoride compound data". OpenMOPAC.net. Retrieved 2007-12-10.
4. ↑ Rh(VII) is known in the RhO₃⁺ cation, see Da Silva Santos, Mayara; Stüker, Tony; Flach, Max; Ablyasova, Olesya S.; Timm, Martin; von Issendorff, Bernd; Hirsch, Konstantin; Zamudio‐Bayer, Vicente; Riedel, Sebastian; Lau, J. Tobias (2022). "The Highest Oxidation State of Rhodium: Rhodium(VII) in [RhO3]+". Angew. Chem. Int. Ed. 61 (38): e202207688. doi:10.1002/anie.202207688. PMC 9544489. PMID 35818987.{{cite journal}}: CS1 maint: article number as page number (link)
5. ↑ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
6. ↑ Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
7. ↑ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
8. ↑ Precious Metal Prices Index taxfreegold.co.uk (HTML). Accessed 19 November 2006.

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