Lenntech: Gadolinium Lenntech: Gadolinium: Physical data, chemical properties, health and environmental effects. (Gadolinium) http://www.lenntech.com/Periodic-chart-elements/Gd-en.htm
WebElements: Gadolinium WebElements: Gadolinium: Extensive information on history, uses, occurrence, compounds, and properties. (Gadolinium) http://www.webelements.com/webelements/elements/text/Gd/key.html
ChemGlobe: Gadolinium ChemGlobe: Gadolinium: Electronic, thermal, and steric data along with an isotope table. (Gadolinium) http://www.vcs.ethz.ch/chemglobe/ptoe/_/64.html
EnvironmentalChemistry.com: Gadolinium EnvironmentalChemistry.com: Gadolinium: Atomic structure, chemical and physical properties, and table of nuclides. (Gadolinium) http://environmentalchemistry.com/yogi/periodic/Gd.html