Editing Group 7 element (section)

==== Technetium ====

{{Main article|Organotechnetium chemistry}}

[[File:Tc CNCH2CMe2(OMe) 6Cation.png|thumb|right|[[Technetium (99mTc) sestamibi]] ("Cardiolite") is widely used for imaging of the heart.]]
Technetium forms a variety of [[coordination complex]]es with organic ligands. Many have been well-investigated because of their relevance to [[nuclear medicine]].<ref>{{cite journal|doi=10.1021/cr1000755|pmid=20415476|title=Technetium and Gallium Derived Radiopharmaceuticals: Comparing and Contrasting the Chemistry of Two Important Radiometals for the Molecular Imaging Era|journal=Chemical Reviews|volume=110|issue=5|pages=2903–20|year=2010|last1=Bartholomä|first1=Mark D.|last2=Louie|first2=Anika S.|last3=Valliant|first3=John F.|last4=Zubieta|first4=Jon}}</ref>

Technetium forms a variety of compounds with Tc–C bonds, i.e. organotechnetium complexes. Prominent members of this class are complexes with CO, arene, and cyclopentadienyl ligands.<ref name="Alberto" /> The binary carbonyl Tc<sub>2</sub>(CO)<sub>10</sub> is a white volatile solid.<ref>{{cite journal|doi = 10.1021/ja01474a038|date = 1961|last1 = Hileman|first1 = J. C.|last2 = Huggins|last3 = Kaesz|journal = Journal of the American Chemical Society |volume = 83|title = Technetium carbonyl|pages = 2953–2954|first2 = D. K.|first3 = H. D.|issue = 13}}</ref> In this molecule, two technetium atoms are bound to each other; each atom is surrounded by [[octahedron|octahedra]] of five carbonyl ligands. The bond length between technetium atoms, 303&nbsp;pm,<ref>{{cite journal|title = The Crystal Structure of Ditechnetium Decacarbonyl|doi =10.1021/ic50030a011|date =1965|last1 =Bailey|first1 = M. F.|journal =Inorganic Chemistry|volume =4|pages =1140–1145|last2 = Dahl|first2 = Lawrence F.|issue = 8}}</ref><ref>{{cite journal|doi = 10.1107/S0365110X62002789|title = Unit cell and space group of technetium carbonyl, Tc2(CO)10|date = 1962|last1 = Wallach|first1 = D.|journal = Acta Crystallographica|volume = 15|page = 1058|issue = 10| bibcode=1962AcCry..15.1058W }}</ref> is significantly larger than the distance between two atoms in metallic technetium (272&nbsp;pm). Similar [[carbonyl]]s are formed by technetium's [[Congener (chemistry)|congeners]], manganese and rhenium.{{sfn|Schwochau|2000|pp=286, 328}} Interest in organotechnetium compounds has also been motivated by applications in [[nuclear medicine]].<ref name="Alberto">{{cite book|doi=10.1007/978-3-642-13185-1_9|chapter=Organometallic Radiopharmaceuticals|title=Medicinal Organometallic Chemistry|volume=32|pages=219–246|series=Topics in Organometallic Chemistry|year=2010 |last1=Alberto|first1=Roger|isbn=978-3-642-13184-4}}</ref> Unusual for other metal carbonyls, Tc forms aquo-carbonyl complexes, prominent being [Tc(CO)<sub>3</sub>(H<sub>2</sub>O)<sub>3</sub>]<sup>+</sup>.<ref name="Alberto" />