Rhodium information, including Technical Data, Safety Data and its high purity properties, research, applications and other useful facts are discussed below. Scientific facts such as the atomic structure, ionization energy, abundance on Earth, conductivity and thermal properties are included.
 Rhodium is a member of the platinum group of metals. It has a higher melting point than platinum, but a lower density. It is alloyed with platinum and palladium in electrodes for spark plugs, advanced laboratory equipment and in thermocouples. Rhodium compounds also have catalytic uses in automotive catalytic converters. Rhodium is used as a plating metal in jewelry production to enhance the whiteness of white gold. Rhodium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity); metals in the form of foil, sputtering target, and rod, and compounds as submicron and nanopowder.
Rhodium facts, including appearance, CAS #, and molecular formula and safety data, research and properties are
available for many specific states, forms and shapes on the product pages listed to the left. Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Nanoparticles and nanopowders provide ultra high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits.
Oxides are available in forms including powders and dense pellets for such  uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Rhodium is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries.
Rhodium is a Block D, Group 9, Period 5 element. The number of electrons in each of Rhodium's shells is 2, 8, 18, 16, 1 and its electronic configuration is [Kr] 4d8 5s1. In its elemental form rhodium's CAS number is 7440-16-6. The rhodium atom has a radius of 134.5.pm and it's Van der Waals radius is 200.pm. Rhodium is not toxic.
 All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, thin fillm deposition using sputtering targets and evaporation materials, metallurgy and optical materials and other high technology applications. Information is provided for stable (non-radioactive) isotopes. Organo-Metallic Rhodium compounds are soluble in organic or non-aqueous solvents. See Analytical Services for information on available certified chemical and physical analysis techniques including MS-ICP, X-Ray Diffraction, PSD and Surface Area (BET) analysis.
Rhodium was first discovered by William Wollaston in 1803.
The name Rhodium, originates from the Greek word 'Rhodon' which means rose.
 Rhodium |
 Rhodium |
 Rodio |
 Ródio |
 Rodio |
 Rhodium |
Abundance. The following table shows the abundance of rhodium and each of its naturally occurring isotopes on Earth along with the atomic mass for each isotope.
| Isotope |
Atomic Mass |
% Abundance on Earth |
| Rh-103 |
102.905504 |
100 |
The following table shows the abundance of Rhodium present in the human body and in the universe scaled to parts per billion (ppb) by weight and by atom:
| |
Typical Human Body |
Universe |
| by Weight |
no data |
0.6 ppb |
| by Atom |
no data |
0.007 ppb |
Safety Data and Biological Role. The safety data for rhodium metal, nanoparticles and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the left margin. Rhodium compounds have no biological role.
Ionization Energy. The ionization energy for rhodium (the least required energy to release a single electron from the atom in it's ground state in the gas phase) is stated in the following table:
| 1st Ionization Energy |
719.68 kJ mol-1 |
| 2nd Ionization Energy |
1744.47 kJ mol-1 |
| 3rd Ionization Energy |
2996.86 kJ mol-1 |
Conductivity. As to rhodium's electrical and thermal conductivity, the electrical conductivity measured as to electrical resistivity @ 20 ºC is 4.51 μΩcm and its electronegativities (or its ability to draw electrons relative to other elements) is 2.28. The thermal conductivity of rhodium is 150 W m-1 K-1.
Thermal Properties. The melting point and boiling point for rhodium are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization.
| Heat of Fusion |
21.55 kJ mol-1 |
| Heat of Vaporization |
494.34 kJ mol-1 |
| Heat of Atomization |
555.59 kJ mol-1 |
Recent Research & Development for RhodiumDirect Access to Parent Amido Complexes of Rhodium and Iridium through N?H Activation of Ammonia.
Mena I, Casado MA, García-Orduña P, Polo V, Lahoz FJ, Fazal A, Oro LA.
Angew Chem Int Ed Engl. 2011 Oct 12. doi: 10.1002/anie.201104745. [Epub ahead of print] No abstract available.
PMID:
21994125
[PubMed - as supplied by publisher]
Asymmetric Hydrogenation of a- and ß-Enamido Phosphonates: Rhodium(I)/Monodentate Phosphoramidite Catalyst.
Zhang J, Li Y, Wang Z, Ding K.
Angew Chem Int Ed Engl. 2011 Oct 11. doi: 10.1002/anie.201104912. [Epub ahead of print] No abstract available.
PMID:
21990114
[PubMed - as supplied by publisher]
An operando DRIFTS investigation into the resistance against CO(2) poisoning of a Rh/alumina catalyst during toluene hydrogenation.
Scalbert J, Meunier FC, Daniel C, Schuurman Y.
Phys Chem Chem Phys. 2011 Oct 11. [Epub ahead of print]
PMID:
21989590
[PubMed - as supplied by publisher]
Rh(III)-Catalyzed Oxidative Olefination of N-(1-Naphthyl)sulfonamides Using Activated and Unactivated Alkenes.
Li X, Gong X, Zhao M, Song G, Deng J, Li X.
Org Lett. 2011 Oct 11. [Epub ahead of print]
PMID:
21988638
[PubMed - as supplied by publisher]
Synthesis of Isochromene and Related Derivatives by Rhodium-Catalyzed Oxidative Coupling of Benzyl and Allyl Alcohols with Alkynes.
Morimoto K, Hirano K, Satoh T, Miura M.
J Org Chem. 2011 Oct 11. [Epub ahead of print]
PMID:
21988500
[PubMed - as supplied by publisher]
Pyridine synthesis from oximes and alkynes via rhodium(iii) catalysis: Cp* and Cp(t) provide complementary selectivity.
Hyster TK, Rovis T.
Chem Commun (Camb). 2011 Oct 10. [Epub ahead of print]
PMID:
21986995
[PubMed - as supplied by publisher]
Rhodium-catalyzed redox allylation reactions of ketones.
Williams FJ, Grote RE, Jarvo ER.
Chem Commun (Camb). 2011 Oct 10. [Epub ahead of print]
PMID:
21984365
[PubMed - as supplied by publisher]
Enantioselective Rhodium(I)-Catalyzed [3+2] Annulations of Aromatic Ketimines Induced by Directed C?H Activations.
Tran DN, Cramer N.
Angew Chem Int Ed Engl. 2011 Oct 4. doi: 10.1002/anie.201105766. [Epub ahead of print] No abstract available.
PMID:
21976453
[PubMed - as supplied by publisher]
Asymmetric N?H Insertion Reaction Cooperatively Catalyzed by Rhodium and Chiral Spiro Phosphoric Acids.
Xu B, Zhu SF, Xie XL, Shen JJ, Zhou QL.
Angew Chem Int Ed Engl. 2011 Oct 4. doi: 10.1002/anie.201105485. [Epub ahead of print] No abstract available.
PMID:
21976452
[PubMed - as supplied by publisher]
Rhodium-Catalyzed Reaction of 1-Alkenylboronates with Aldehydes Leading to Allylation Products.
Shimizu H, Igarashi T, Miura T, Murakami M.
Angew Chem Int Ed Engl. 2011 Oct 4. doi: 10.1002/anie.201105148. [Epub ahead of print] No abstract available.
PMID:
21976365
[PubMed - as supplied by publisher]
Rhodium-Catalyzed Annulation of N-Benzoylsulfonamide with Isocyanide through C?H Activation.
Zhu C, Xie W, Falck JR.
Chemistry. 2011 Oct 4. doi: 10.1002/chem.201102475. [Epub ahead of print] No abstract available.
PMID:
21972033
[PubMed - as supplied by publisher]
"Cofactor"-Controlled Enantioselective Catalysis.
Dydio P, Rubay C, Gadzikwa T, Lutz M, Reek JN.
J Am Chem Soc. 2011 Oct 11. [Epub ahead of print]
PMID:
21961536
[PubMed - as supplied by publisher]
Selective hydroformylation-hydrogenation tandem reaction of isoprene to 3-methylpentanal.
Behr A, Reyer S, Tenhumberg N.
Dalton Trans. 2011 Sep 29. [Epub ahead of print]
PMID:
21960209
[PubMed - as supplied by publisher]
Synthesis of a,a-Disubstituted Aryl Amines by Rhodium-Catalyzed Amination of Tertiary Allylic Trichloroacetimidates.
Arnold JS, Cizio GT, Nguyen HM.
Org Lett. 2011 Oct 21;13(20):5576-9. Epub 2011 Sep 29.
PMID:
21958228
[PubMed - in process]
Unravelling the Reaction Path of Rhodium-MonoPhos-Catalysed Olefin Hydrogenation.
Alberico E, Baumann W, de Vries JG, Drexler HJ, Gladiali S, Heller D, Henderickx HJ, Lefort L.
Chemistry. 2011 Sep 28. doi: 10.1002/chem.201101793. [Epub ahead of print]
PMID:
21956660
[PubMed - as supplied by publisher]
Fluorous Hydrosilylation.
Carreira M, Contel M.
Top Curr Chem. 2011 Sep 28. [Epub ahead of print]
PMID:
21952841
[PubMed - as supplied by publisher]
The oxidative conversion of the N,S-bridged complexes [{RhLL'(µ-X)}(2)] to [(RhLL')(3)(µ-X)(2)](+) (X = mt or taz): a comparison with the oxidation of N,N-bridged analogues.
Blagg RJ, López-Gómez MJ, Charmant JP, Connelly NG, Cowell JJ, Haddow MF, Hamilton A, Orpen AG, Riis-Johannessen T, Saithong S.
Dalton Trans. 2011 Sep 27. [Epub ahead of print]
PMID:
21952645
[PubMed - as supplied by publisher]
Ligand Fluorination to Optimize Preferential Oxidation (PROX) of Carbon Monoxide by Water-Soluble Rhodium Porphyrins.
Biffinger JC, Uppaluri S, Sun H, Dimagno SG.
ACS Catal. 2011 May 18;1(7):764-771.
PMID:
21949596
[PubMed]
Rhodium-Catalyzed Intermolecular [2+2+2] Cross-Trimerization of Aryl Ethynyl Ethers and Carbonyl Compounds To Produce Dienyl Esters.
Miyauchi Y, Kobayashi M, Tanaka K.
Angew Chem Int Ed Engl. 2011 Sep 21. doi: 10.1002/anie.201105519. [Epub ahead of print] No abstract available.
PMID:
21948312
[PubMed - as supplied by publisher]
Zinc-catalyzed allenylations of aldehydes and ketones.
Fandrick DR, Saha J, Fandrick KR, Sanyal S, Ogikubo J, Lee H, Roschangar F, Song JJ, Senanayake CH.
Org Lett. 2011 Oct 21;13(20):5616-9. Epub 2011 Sep 26.
PMID:
21942658
[PubMed - in process]
|
| Formula |
Atomic Number |
Molecular Weight |
Electronegativity (Pauling) |
Density |
Melting Point |
Boiling Point |
Vanderwaals radius |
Ionic radius |
Energy of first ionization |
| Rh |
45 |
102.91 g.mol -1 |
2.2 |
12.4 g.cm-3 at 20 °C |
1970 °C |
3727 °C |
200.pm |
unknown |
719.68 kJ.mol-1 |
|
