Iron(III) thiocyanate, Fe(SCN)2+ is a complex ion formed in situ and the concentration is dependent upon the state of equilibrium, which is mostly shown qualitatively rather than quantitatively.
We provide the following links with useful information:
- 'Stressing an Equilibrium System by Changing the Concentration of Ions in Solution', University of Illinois at Urbana-Champagn website, http://www.chem.uiuc.edu/chem103/equilibrium/iron.htm (Accessed August 2016). This activity uses 0.0020M KSCN which is diluted to produce 0.0010M KSCN, to which 5 drops of 0.02 M Fe(NO3)3 is added.
- 'Experiment 1 Chemical Equilibria and Le Châtelier’s Principle', Colby College, Chemistry website, http://www.colby.edu/chemistry/CH142L/Expt1.pdf (2012) This is a more quantitative activity using KSCN and Fe(NO3)3
- 'The effect of concentration changes on equilibria', Creative Chemistry website, https://www.creative-chemistry.org.uk/documents/N-ch2-12.pdf (Accessed August 2016). This uses more concentrated solutions of KSCN and FeCl3