Reinecke's salt

Reinecke's salt
Structural formulas of the ammonium cation and the tetrathiocyanato-diamminechromate(III) anion
Red powder on a watch glass
Names
IUPAC name
ammonium (OC-6-11)-diamminetetrakis(thiocyanato-N)chromate(1−)
Other names
ammonium tetrathiocyanato-
diamminechromate(III),

Reinecke salt,

ammonium reineckate
Identifiers
CAS Number
  • 13573-16-5 checkY
3D model (JSmol)
  • Interactive image
ChemSpider
  • 21106473 checkY
ECHA InfoCard 100.033.625 Edit this at Wikidata
EC Number
  • 237-003-3
PubChem CID
  • 159682
UNII
  • JL96S212CS checkY
CompTox Dashboard (EPA)
  • DTXSID10894851 Edit this at Wikidata
InChI
  • InChI=1S/4CNS.Cr.3H3N.H2O/c4*2-1-3;;;;;/h;;;;;3*1H3;1H2/q4*-1;+3;;;;/p+1 checkY
    Key: GXUDINOISGOIAV-UHFFFAOYSA-O checkY
  • InChI=1/4CNS.Cr.3H3N.H2O/c4*2-1-3;;;;;/h;;;;;3*1H3;1H2/q4*-1;+3;;;;/p+1/rC4H6CrN6S4.H3N.H2O/c6-5(7,8-1-12,9-2-13,10-3-14)11-4-15;;/h6-7H3;1H3;1H2/q-1;;/p+1
    Key: GXUDINOISGOIAV-JJHXSEQHAU
  • [NH4+].S=C=N/[Cr-3]([NH3+])([NH3+])(/N=C=S)(/N=C=S)/N=C=S.O
Properties
Chemical formula
 C4H12N7OCrS4
Molar mass 354.42 g/mol
Appearance dark red solid
Density 1.49 g/cm3[1]
Melting point 270 °C (518 °F; 543 K)
Boiling point decomposes
Solubility in water
 soluble in hot water
Structure
Coordination geometry
 octahedral
Dipole moment
 0 D
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 toxic
GHS labelling:
Pictograms
 GHS07: Exclamation markGHS09: Environmental hazard
Warning
H302, H312, H332, H410
P261, P264, P270, P271, P273, P280, P301+P312, P302+P352, P304+P312, P304+P340, P312, P322, P330, P363, P391, P501
Related compounds
Related compounds
 [Co(NH3)6]Cl3,
KSCN,
Chromium(III) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references
Chemical compound

Reinecke's salt is an inorganic compound with the formula NH4[Cr(NCS)4(NH3)2]·H2O. The dark-red crystalline compound is soluble in boiling water, acetone, and ethanol.[2] It can be classified as a metal isothiocyanate complex.

Structure, preparation, reactions

The chromium atom is surrounded by six nitrogen atoms in an octahedral geometry. The NH3 ligands are mutually trans and the Cr–NCS groups are linear. The salt crystallizes with one molecule of water.[1]

It was first reported in 1863.[3] NH4[Cr(NCS)4(NH3)2] is prepared by treatment of molten NH4SCN (melting point around 145–150 °C) with (NH4)2Cr2O7.[4]

This salt was once widely used to precipitate primary and secondary amines as their ammonium salts. Included in the amines that effectively form crystalline precipitates are those derived from the amino acids, including proline and hydroxyproline. It also reacts with Hg2+ compounds, giving a red color or a red precipitate.

References

  1. ^ a b Saito, Y.; Takeuchi, Y.; Pepinsky, R. (1955). "The Crystal Structure of Ammonium Reineckate". Zeitschrift für Kristallographie, Kristallgeometrie, Kristallphysik, Kristallchemie. 106 (1–6): 476–477. doi:10.1524/zkri.1954.106.16.476. S2CID 101134761.
  2. ^ Peppel, T.; Schmidt, C.; Köckerling, M. (2011). "Synthesis, Properties, and Structures of Salts with the Reineckate Anion, [CrIII(NCS)4(NH3)2]−, and Large Organic Cations". Zeitschrift für Anorganische und Allgemeine Chemie. 637 (10): 1314–1321. doi:10.1002/zaac.201100091.
  3. ^ Reinecke, A. (1863). "Über Rhodanchromammonium-Verbindungen". Annalen der Chemie und Pharmacie. 126: 113–118. doi:10.1002/jlac.18631260116.
  4. ^ Dakin, H. D. (1935). "Reinecke Salt". Organic Syntheses. 15: 74. doi:10.15227/orgsyn.015.0074.