rhodium

• Description
• General information
• Physical data
• Radii
• Electronegativities
• Solid state structure
• Temperatures
• Enthalpies
• Ionization Enthalpies
• Isotopes
• Further information

Description

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.

General information

Discoveror: William Hyde Wollaston
Date discovered: 1803
Discovered at: England
Meaning of name: From the Greek word "rhodon" meaning "rose"

Physical data

Standard state: solid at 298 K
Colour: silvery white metallic
Density of solid at ambient temperature/kg m^-3: 12450
Molar volume/cm³: 8.28

Radii /pm

Atomic: 173
Covalent (single bond):
Pauling radius for the ion [Rh]^-: no data

Valence shell orbital radius maxima (R_max)

orbital	s	p	d	f
radius	160.4	no data	60.4	no data

Electronegativities

Both values are quoted on the Pauling scale.

Pauling: 2.28
Allred Rochow: 1.45

Crystal Structure

structure: ccp (cubic close-packed)

The following CrystalMaker image represents the solid state structure. For most elements, the most stable allotrope is illustrated. Try WebElements version 2 for interactive virtual reality and CHIME images.

Temperatures (/K)

melting point: 2237
boiling point: 3968

Enthalpies /kJ mol^-1

fusion: 26.6
vaporization: 494

single bond enthalpies:

Rh-F	Rh-Cl	Rh-Br	Rh-I	Rh-Rh
no data	no data	no data	no data	285.4

Ionization enthalpies /kJ mol^-1

Number	Enthalpy
1st	720
2nd	1744
3rd	2997

Isotopes

This section gives some data for naturally occurring isotopes.

Nominal mass	Accurate mass	% natural abundance
103Rh	102.905500 (4)	100

Further Information

• Additional information about WebElements 1.2.2
• This is a licensed copy (here is the full list) of WebElements 1.2.2 and contains a subset of the material contained within the main version of WebElements (version 2)
• For further information please try WebElements version 2
• Sheffield Chemdex: perhaps the largest internet chemistry directory
• Sheffield Chemputer: interactive chemistry calculators on the WWW