Gadolinium(III) chloride, also known as gadolinium trichloride, is GdCl₃. It is a colorless, hygroscopic, water-soluble solid. The hexahydrate GdCl₃∙6H₂O is commonly encountered and is sometimes also called gadolinium trichloride. Gd species are of special interest because the ion has the maximum number of unpaired spins possible, at least for known elements. With seven valence electrons and seven available f-orbitals, all seven electrons are unpaired and symmetrically arranged around the metal. The high magnetism and high symmetry combine to make Gd a useful component in NMR spectroscopy and MRI.