d-block

This article is about a class of chemical elements. For the hip hop record label, see D-Block Records. For the hardstyle duo, see D-Block & S-te-Fan.

The d-block is the portion of the periodic table that contains the element groups 3-12.^[1][2] These groups correspond to the filling of the atomic d-orbital subshell, with electron configurations ranging from s²d¹ (Group 3) to s²d¹⁰ (Group 12). There are some irregularities in the sequence; for example Cr is s¹d⁵ (not s²d⁴) and the Group 11 metals are s¹d¹⁰ (not s²d⁹), so that the d-subshell is actually complete at Group 11.

The d-block elements are often also known as transition metals or transition elements. However the exact limits of the transition metal region are usually not considered to be identical to the d-block. Although some authors do identify the entire d-block as transition metals,^[1] most define transition metals as elements with partly filled d subshells either in the neutral atom or in ions in common oxidation states.^[2][3] This definition has now been adopted by IUPAC^[4] and corresponds to including only Groups 3-11 as transition metals. Group 12 metals lack the characteristic chemical and physical properties associated with incomplete d subshells and are considered post-transition metals. Jensen has reviewed the historical usage of the terms transition element (or metal) and d-block.^[5]

In the s-block and p-block of the periodic table, similar properties across the periods are generally not observed: the most important similarities tend to be vertical, down groups. However the d-block is notable in that horizontal similarities across the periods do become important.

Although Lutetium and Lawrencium are in the d-block, they are not considered transition metals but a lanthanide and an actinide, respectively, according to IUPAC.^[6] Group 12 elements are also in the d-block but are considered post-transition metals as their d-subshell is completely filled.^[6]

Chemical elements in d-block

Group →	3	4	5	6	7	8	9	10	11	12
↓ Period
4	21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn
5	39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd
6	71 Lu	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg
7	103 Lr	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn

See also

• Electron configuration

References

1. ^ ^{a b} R.H. Petrucci, W.S. Harwood and F.G. Herring “General Chemistry” (8th ed, Prentice-Hall 2002), p.341-2
2. ^ ^{a b} C.E. Housecroft and A.G. Sharpe “Inorganic Chemistry” (2nd ed, Pearson Prentice-Hall 2005), p..20-21
3. ^ F.A. Cotton and G. Wilkinson “Advanced Inorganic Chemistry” (5th ed, John Wiley 1988) p.625
4. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "transition element".
5. ^ Jensen, William B. (2003). "The Place of Zinc, Cadmium, and Mercury in the Periodic Table". Journal of Chemical Education 80 (8): 952–961. Bibcode 2003JChEd..80..952J. doi:10.1021/ed080p952. http://www.uv.es/~borrasj/ingenieria_web/temas/tema_1/lecturas_comp/p952.pdf. 
6. ^ ^{a b} IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004) (online draft of an updated version of the "Red Book" IR 3-6)