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8/12/2019 Thio Cyan Ate
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ThiocyanateFrom Wikipedia, the free encyclopedia
Thiocyanate
IUPAC name [hide]
cyanosulfanide
Other names[hide]
sulphocyanate, thiocyanide
Identifiers
PubChem 9322
ChemSpider 8961
Ch!" C#!"$18%22
Ch&!' C#&!'8(336
)mol*3+ imaes "mae 1
SMILES
[sho-]
InChI
[sho-]
Properties
&olecular formula SC .*
&olar mass /80%82(
erify -hat is$ 4 5
cept -here noted other-ise, data are ien for materials in their standard
state at 2/ 7C 7, 1%% :Pa
"nfobo references
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Thiocyanate (also known as rhodanide) is the anion [SCN]− !t is the con"#$ate %ase of thiocyanic acid
Common deri&ati&es incl#de the colo#rless salts potassi#m thiocyanateand sodi#m thiocyanate 'r$anic
compo#nds containin$ the f#nctional $ro#p SCN are also called thiocyanates erc#ry(!!) thiocyanate was
formerly #sed in pyrotechnics
Thiocyanate is analo$o#s to the cyanate ion, ['CN]−, wherein oy$en is replaced %ys#lf#r [SCN]− is one of
the pse#dohalides, d#e to the similarity of its reactions to that of halide ions Thiocyanate #sed to %e known
as rhodanide (from a *reek word for rose) %eca#se of the red colo#r of its complees with iron
Thiocyanate is prod#ced %y the reaction of elemental s#lf#r or thios#lfate with cyanide+
CN− - S . SCN−
CN− - S/'0/− . SCN− - S'0
/−
The second reaction is cataly1ed %y the en1yme s#lfotransferase known as rhodanase and may
%e rele&ant to detoification of cyanide in the %ody
Contents
[hide]
• 2 Str#ct#re, %ondin$ and coordination chemistry
• / 'r$anic thiocyanates
• 0 Test for iron(!!!)
• 3 4iolo$ical chemistry of thiocyanate in medicine
• 5 6eferences
Str#ct#re, %ondin$ and coordination chemistry[edit]
6esonance str#ct#res of the thiocyanate ion
Thiocyanate shares its ne$ati&e char$e approimately e7#ally %etween s#lf#r and nitro$en 8s a
conse7#ence, thiocyanate can act as a n#cleophile at either s#lf#r or nitro$en 9 it is
an am%identate li$and [SCN]− can also %rid$e two (−SCN−) or e&en three metals (:SCN− or
−SCN;) <perimental e&idence leads to the $eneral concl#sion that class 8 metals (hard acids)
tend to form N =%onded thiocyanate complees, whereasclass 4 metals (soft acids) tend to form S =
%onded thiocyanate complees 'ther factors, e$ kinetics and sol#%ility, are sometimes in&ol&ed,
and linka$e isomerism can occ#r, for eample [Co(N> 0)5(NCS)]Cl/ and [Co(N>0)5(SCN)]Cl/[2]
'r$anic thiocyanates[edit]
8/12/2019 Thio Cyan Ate
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'r$anic and transition metal deri&ati&es of the thiocyanate ion can eist as ? linka$e isomers? !n
thiocyanates, the or$anic $ro#p (or metal ion) is attached to s#lf#r+ 6−S−C@N has a S=C sin$le
%ond and a C=N triple %ond[/] !n isothiocyanates, the s#%stit#ent is attached to nitro$en+
6−NACAS has a S=C do#%le %ond and a C=N do#%le %ond+
Bhenylthiocyanate and phenylisothiocyanate are linka$e isomers and are %onded differently
'r$anic thiocyanates are hydroly1ed to thiocar%amates in the 6iemschneider thiocar%amate
synthesis
Test for iron(!!!)[edit]
!f [SCN]− is added to a sol#tion containin$ iron (!!!) ions (Fe0-), a %lood red sol#tion is formed d#e
to the formation of [Fe(NCS)(>/')5]/-
•
The %lood=red colo#red comple pentaa7#a(thiocyanato=N )iron(!!!), [Fe(NCS)(>/')5]/-, indicates the
presence of Fe0- in sol#tion
•
!ron(!!!) test]]
4iolo$ical chemistry of thiocyanate in medicine[edit]
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Thiocyanate[0] is known to %e an important part in the %iosynthesis of hypothiocyanite %y
a lactoperoidase[3][5][] Th#s the complete a%sence of thiocyanate[D] or red#ced thiocyanate[] in
the h#man %ody, (e$, cystic fi%rosis) is dama$in$ to the h#man host defense system [E]
[2] Thiocyanate is a potent competiti&e inhi%itor of the thyroid sodi#m=iodide symporter [22]
Thiocyanate is a meta%olite of sodi#m nitropr#sside, after rhodanese catalyses its reaction
with thios#lfate