Rutherfordium - Rf General Information Discovery The two different isotopes of rutherfordium were discovered in 1964 and 1969 by various parties at Dubna, Moscow and Berkeley, California respectively. Appearance Unknown, but probably metallic grey in appearance. Source A transuranium element created by bombarding 249Cf with 12C nuclei. Uses Unknown. Biological Role None. General Information Two separate groups claimed to be the discoverers of the element, due to two different isotopes. A synthetic element created via nuclear bombardment, few atoms have ever been made and the properties of rutherfordium are very poorly understood. It is a radioactive metal and is of research interest only.

	Physical Information
	Atomic Number		104
	Relative Atomic Mass (12C=12.000)		261.11
	Melting Point/K		2400 (estimated)
	Boiling Point/K		5800 (estimated)
	Density/kg m-3		23,000
	Ground State Electron Configuration		[Rn]5f146d27s2
	Electron Affinity(M-M-)/kJ mol-1		not available

	Key Isotopes
	nuclide	253Rf	255Rf	256Rf	257Rf	258Rf
	atomic mass				257.10	258.10
	natural abundance	0%	0%	0%	0%	0%
	half-life	1.5 secs	1.4 secs	7x10-3 secs	4.8 secs	0.013 secs
	nuclide	259Rf	260Rf	261Rf	262Rf
	atomic mass	259.11	260.11	261.11
	natural abundance	0%	0%	0%	0%
	half-life	3.0 secs	0.020 secs	65 secs	0.047 secs

Other Information
Enthalpy of Fusion/kJ mol-1		n/a
Enthalpy of Vaporisation/kJ mol-1		n/a
Oxidation States
Rf+4 has been predicted as the most stable.

	Ionisation Energies/kJ mol-1
	M - M+	490 (est)
	M+ - M2+
	M2+ - M3+
	M3+ - M4+
	M4+ - M5+
	M5+ - M6+
	M6+ - M7+
	M7+ - M8+
	M8+ - M9+
	M9+ - M10+