What Is Gadolinium?

Gadolinium, atomic number 64 and symbol Gd, belongs to the lanthanides — the row of rare earth elements beneath the main periodic table.

Has the highest neutron absorption of any element. Used as MRI contrast agent.

As a lanthanide in Period 6 and Group 3 (Transition Metals), gadolinium's placement on the table reflects its electron configuration of [Xe] 4f⁷ 5d¹ 6s², which governs its bonding behavior and the type of compounds it typically forms.

Position on the Periodic Table

Gadolinium is located in Period 6, an unusually long row that includes the entire lanthanide series.

Within that row, gadolinium sits in Group 3 (Transition Metals), alongside elements that share a similar number of valence electrons and, by extension, similar chemical behavior.

This position is not arbitrary — the periodic table was deliberately organized so that an element's row and column reveal its expected reactivity, bonding pattern, and physical state at a glance.

Physical & Chemical Properties

Gadolinium has an atomic mass of 157.250 u and a density of 7.90 g/cm³. Its melting point is 1313°C and its boiling point is 3273°C.

Gadolinium displays the typical lanthanide combination of a silvery appearance and chemistry dominated by its f-orbital electrons.

Electron Configuration Explained

Gadolinium's electron configuration is [Xe] 4f⁷ 5d¹ 6s², describing how its electrons are distributed across shells and subshells around the nucleus.

Reading the configuration in order shows electrons filling shells of increasing energy, following the standard Aufbau principle that explains how atomic structure builds up across the periodic table.

The outermost (valence) electrons shown in this configuration are what ultimately determine gadolinium's chemical reactivity and the type of bonds it forms with other elements.

History & Discovery

Gadolinium was formally discovered in 1880, J.C.G. de Marignac, identified through the careful isolation and analytical techniques typical of that era's chemical research.

Many elements from this period were anticipated by Dmitri Mendeleev's periodic table, which successfully predicted gaps corresponding to undiscovered elements well before laboratory instruments existed to confirm them directly.

What Is Gadolinium Used For?

Gadolinium's specific properties make it useful in several applications, including:

  • MRI contrast agents
  • Nuclear reactor shielding
  • Magnetocaloric refrigeration
  • Phosphors
  • Alloys

These uses reflect gadolinium's underlying classification as a lanthanide, since the same properties that define its category in chemistry also determine where it becomes practically useful.

Fun Facts About Gadolinium

  • Gadolinium MRI contrast agents make blood vessels and tumors clearly visible.
  • Gadolinium is element number 64 on the periodic table, in Period 6 and Group 3.
  • Its standard atomic mass is 157.250 u, calculated from the natural abundance of its isotopes.

Frequently Asked Questions

What is Gadolinium's atomic number?
Gadolinium has atomic number 64.

What is Gadolinium's chemical symbol?
Gadolinium's symbol is Gd.

What group and period is Gadolinium in?
Gadolinium is in Period 6, Group 3 (Transition Metals).

What is Gadolinium's atomic mass?
Gadolinium's standard atomic mass is 157.250 u.