Periodic Table


October 31, 2011, 4:41 pm
Previous Element: Technetium

Next Element: Rhodium


Physical Properties
Color silvery-white
Phase at Room Temp. solid
Density (g/cm3) 12.41
Hardness (Mohs) 6.5
Melting Point (K) 2583.2
Boiling Point (K) 4323
Heat of Fusion (kJ/mol) 25.522
Heat of Vaporization (kJ/mol) 619
Heat of Atomization (kJ/mol) 643
Thermal Conductivity (J/m sec K) 117
Electrical Conductivity (1/mohm cm) 131.579
Source Nickel ores (sulfides)
Atomic Properties
Electron Configuration [Kr]5s14d7
Number of Isotopes 37 (7 natural)
Electron Affinity (kJ/mol) 101
First Ionization Energy (kJ/mol) 711.1
Second Ionization Energy (kJ/mol) 1617.1
Third Ionization Energy (kJ/mol) 2746.9
Electronegativity 2.2
Polarizability (Å3) 9.6
Atomic Weight 101.07
Atomic Volume (cm3/mol) 8.1
Ionic Radius2- (pm) ---
Ionic Radius1- (pm) ---
Atomic Radius (pm) 134
Ionic Radius1+ (pm) ---
Ionic Radius2+ (pm) ---
Ionic Radius3+ (pm) 82
Common Oxidation Numbers +3, +4
Other Oxid. Numbers -2, +1, +2, +5, +6, +7, +8
In Earth's Crust (mg/kg) 1.00x10-3
In Earth's Ocean (mg/L) 7.0x10-7
In Human Body (%) 0%
Regulatory / Health
CAS Number 7440-18-8
OSHA Permissible Exposure Limit (PEL) No limits
OSHA PEL Vacated 1989 No limits
NIOSH Recommended Exposure Limit No limits
Mineral Information Institute
Jefferson Accelerator Laboratory

Ruthenium is a relatively inert chemical element with atomic number 44. It is a rare transition metal with atomic symbol Ru that belongs  within the platinum group of metals within the periodic table. As in the case of other metals of the platinum group, ruthenium is relatively unreactive as a chemical element. 

This article is written at a definitional level only. Authors wishing to improve this entry are inivited to expand the present treatment, which additions will be peer reviewed prior to publication of any expansion.


(2011). Ruthenium. Retrieved from


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