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]

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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