how are other metals similar to transition metals

Post-transition metal - Wikipedia, the free encyclopedia


** Post-transition metal **

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Post-transition metals in the periodic table

  Elements classified as post-transition metals by Masterton, Hurley and
Neth:^[1]Ga, In, Tl, Sn, Pb, Bi, Po
  Also recognised by Huheey, Keiter and Keiter:^[2]Al, Ge, Sb, Po; and by
Cox:^[3]Zn, Cd, Hg
  Also recognised by Deming:^[4]Cu, Ag, Au (but he counted Al and groups
1 and 2 as 'light metals')^[n 1]
  Elements that might be post-transition metals: At, Cn, Uut, Fl, Uup,
Lv, Uus

In chemistry, *post-transition metals* are the metallic elements in the
periodic table located between the transition metals (to their left) and
the metalloids (to their right). Usually included in this category are
gallium, indium and thallium; tin and lead; and bismuth. Which elements are
counted as post-transition metals depends, in periodic table terms, on
where the transition metals are taken to end and where the metalloids or
non-metals are taken to start.

Physically, post-transition metals are soft (or brittle), have poor
mechanical strength, and melting points lower than those of the transition
metals; most also have boiling points lower than those of the transition
metals. Being close to the metal-nonmetal border, their crystalline
structures tend to show covalent or directional bonding effects, having
generally greater complexity or fewer nearest neighbours than other
metallic elements.

Chemically, they are characterised—to varying degrees—by covalent
bonding tendencies, acid-base amphoterism and the formation of anionic
species such as aluminates, stannates, and bismuthates (in the case of
aluminium, tin, and bismuth, respectively). They can also form Zintl phases
(half-metallic compounds formed between highly electropositive metals and
moderately electronegative metals or metalloids).

The expression 'post-transition metals' is used here as there is no
IUPAC-approved collective name for these metals. Occasionally, some or all
of them have instead


© 2005-2019