Rhodium 45 Rh 102.90550(2)   Switch element to... actinium aluminium aluminum americium antimony argon arsenic astatine barium berkelium beryllium bismuth bohrium boron bromine cadmium caesium calcium californium carbon cerium cesium chlorine chromium cobalt copper curium darmstadtium dubnium dysprosium einsteinium erbium europium fermium fluorine francium gadolinium gallium germanium gold hafnium hassium helium holmium hydrogen indium iodine iridium iron krypton lanthanum lawrencium lead lithium lutetium magnesium manganese meitnerium mendelevium mercury molybdenum neodymium neon neptunium nickel niobium nitrogen nobelium osmium oxygen palladium phosphorus platinum plutonium polonium potassium praseodymium promethium protactinium radium radon rhenium rhodium roentgenium rubidium ruthenium rutherfordium samarium scandium seaborgium selenium silicon silver sodium strontium sulfur sulphur tantalum technetium tellurium terbium thallium thorium thulium tin titanium tungsten ununbium ununhexium ununoctium ununpentium ununquadium ununtrium uranium vanadium xenon ytterbium yttrium zinc zirconium Go adjacent... Fe Co Ni Ru Rh Pd Os Ir Pt

The essentials

Description 

Here is a brief description of rhodium.

• Standard state: solid at 298 K
• Colour: silvery white metallic
• Classification: Metallic
• Availability:

  rhodium is available in several forms including foil, sponge, "rhodium black", and wire.

Ruthenium, rhodium, palladium, osmium, iridium, and platinum together make up a group of elements referred to as the platinum group metals (PGM).

Small and large samples of rhodium wire like this can be purchased via their web catalogue from from Advent Research Materials via their web catalogue.

Rhodium metal is silvery white. Rhodium has a higher melting point and lower density than platinum. It has a high reflectance and is hard and durable. Upon heating it turns to the oxide when red and at higher temperatures turns back to the element. It is a major component of industrial catalytic systems such as the BP-Monsanto process.

Isolation

It would not normally be necessary to make a sample of rhodium in the laboratory as the metal is available, at a price, commercially. The industrial extraction of rhodium is complex as the metal occurs in ores mixed with other metals such as palladium, silver, platinum, and gold. Sometimes extraction of the precious metals such as rhodium, platinum and palladium is the main focus of a partiular industrial operation while in other cases it is a byproduct. The extraction is complex because of the other metals present and only worthwhile since rhodium is the basis of very important catalysts in industry.

Preliminary treatment of the ore or base metal byproduct is required to remove silver, gold, palladium, and platinum. The resulting residue is melted with sodium bisulphate (NaHSO₄) and the resulting mixture extracted water to give a solution containing rhodium sulphate, Rh₂(SO₄)₃. The rhodium is precipitated out as the hydroxide by addition of sodium hydroxide, NaOH, and redissolved in hydrochloric acid, HCl, to give H₃RhCl₆. This is treated with NaNO₂ and NH₄Cl to form a precipitate of the rhodium complex (NH₄)₃[Rh(NO₂)₆]. Dissolution of the precipitate in HCl gives a solution of pure (NH₄)₃RhCl₆. Evaporation to dryness and burning under hydrogen gas gives pure rhodium.

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