Copper(II) thiocyanate

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Copper(II) thiocyanate
CuNCS2 cropped.png
Copper(II) thiocyanate
CuNCS2 crystal structure.png
Crystal structure of copper(II) thiocyanate
Other names
Cupric thiocyanate
3D model (JSmol)
  • InChI=1S/2CHNS.Cu/c2*2-1-3;/h2*3H;/q;;+2/p-2
  • C(#N)[S-].C(#N)[S-].[Cu+2]
Molar mass 179.71 g/mol[1]
Appearance black powder
Density 2.47 g/cm3[1]
Melting point decomposes at 180 C[2]
0.66·10−3 cm3/mol[1]
Related compounds
Other anions
Copper(II) bromide, Copper(II) chloride
Other cations
Copper(I) thiocyanate, Cobalt(II) thiocyanate, Mercury(II) thiocyanate, Ammonium thiocyanate
Potassium thiocyanate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Copper(II) thiocyanate (or cupric thiocyanate) is a coordination polymer with formula Cu(SCN)2.[1] It is a black solid which slowly decomposes in moist air.[2] It was first reported in 1838 by Carl Ernst Claus and its structure was determined first in 2018.[3][1]


The structure of Cu(SCN)2 was determined via powder X-ray diffraction and consists of chains of Cu(NCS)2 linked together by weak Cu-S-Cu bonds into two-dimensional layers. It can be considered a Jahn-Teller distorted analogue of the mercury thiocyanate structure-type. Each copper is octahedrally coordinated by four sulfurs and two nitrogens. The sulfur end of the SCN- ligand is doubly bridging.[1]


Copper(II) thiocyanate can be prepared from the reaction of concentrated solutions of copper(II) and a soluble thiocyanate salt in water, precipitating as a black powder.[2][3] With rapid drying, pure Cu(SCN)2 can be isolated. Reaction at lower concentrations and for longer periods of time generates instead copper(I) thiocyanate.[4]


Copper(II) thiocyanate, like copper(II) bromide and copper(II) chloride, is a quasi low-dimensional antiferromagnet and it orders at 12K into a conventional Néel ground state.[1]


  1. ^ a b c d e f g Cliffe, Matthew J.; Lee, Jeongjae; Paddison, Joseph A. M.; Schott, Sam; Mukherjee, Paromita; Gaultois, Michael W.; Manuel, Pascal; Sirringhaus, Henning; Dutton, Siân E.; Grey, Clare P. (2018-04-25). "Low-dimensional quantum magnetism in Cu ( NCS ) 2 : A molecular framework material". Physical Review B. 97 (14): 144421. doi:10.1103/PhysRevB.97.144421. ISSN 2469-9950.
  2. ^ a b c Hunter, J. A.; Massie, W. H. S.; Meiklejohn, J.; Reid, J. (1969-01-01). "Thermal rearrangement in copper(II) thiocyanate". Inorganic and Nuclear Chemistry Letters. 5 (1): 1–4. doi:10.1016/0020-1650(69)80226-6. ISSN 0020-1650.
  3. ^ a b Claus, C. (1838). "Beiträge zur näheren Kenntniss der Schwefelcyanmetalle". Journal für Praktische Chemie. 15 (1): 401–411. doi:10.1002/prac.18380150142. ISSN 1521-3897.
  4. ^ Smith, D. L.; Saunders, V. I. (15 March 1982). "Preparation and structure refinement of the 2H polytype of β-copper(I) thiocyanate". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 38 (3): 907–909. doi:10.1107/S0567740882004361.