(SCN)2 - THIOCYANOGEN

Properties of thiocyanogen:

It is white (sometimes with a yellowish tint), unstable at low temperatures. It has the structure of NCS-SCN. Under normal conditions, quickly polymerizes into red (SCN)(n). It is readily soluble in water (with partial decomposition), rapidly decomposes in the presence of dissolved oxygen. It is readily soluble in carbon disulfide and carbon tetrachloride; slowly decomposes in non-aqueous solutions. On chemical properties is similar to I2. It is weak oxidant and reductant.


Molar mass g/mol 116.17
Melting point °C -2

Methods for preparation of thiocyanogen:

2KNCS + 2H2SO4(diluted) + MnO2 = (SCN)2 + MnSO4 + 2H2O + K2SO4 (0° C).

2KNCS(solution) + I2 = 2KI + (SCN)2 (0° C).

NH4NCS(solution) + I2 = 2NH4I + (SCN)2 (0° C).

2NH4NCS+2H2SO4(diluted)+MnO2 = (SCN)2+MnSO4 +2H2O+(NH4)2SO4 (0° C).

2AgNCS + Br2(cold) = 2AgBr↓ + (SCN)2 (in liquid CS2).


Chemical reactions with thiocyanogen:

(n)(SCN)2 = 2(SCN)(n) [above 20° C].

3(SCN)2 + 4H2O = time = HCN + 5HNCS + H2SO4,

(SCN)2 + O2 + 2H2O = time = HCN + HNCS + H2SO4 (time = 30 min).

(SCN)2 + 16HNO3(conc.) = 2H2SO4 + 2CO2↑ +2NH4NO3 + 14NO2↑ + 2H2O.

(SCN)2(solution) + 2Na = 2NaNCS.

(SCN)2 + 3KI(conc.) = 2KNCS + K[I(I2)].

(SCN)2 + KNCS(conc.) + 6H2O = [K(H2O)6](+) + (NCS)(-)3 .


 

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DNA is flame retardant.