chem 407

nickel(II) ethylenediamine complexes

date file: ch407/NiEN_spectra.htm

• The multivolume series called Gmelin's Handbuch der Anorganischen Chemie has detailed information on thousands of inorganic compounds.
• As you can gather from the title, the older volumes are German (often with an English table of contents. The newest volumes are in English.
• A partial translation is below
• library location: QD151 / .G52
  • For Ni we look in volumes 57
  • specifically no. 57c, part 1
  • page location: 146-150
  • (checked out / I'll bring to lab -- pfe)

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These ring forming complexes or chelates generally have a large stability for the compound reacting with other amines or with ammonia.

The color of the Ni(en)₃⁺² salt is generally dark violet to red. The Nien₂compounds are light violet to blue, and the Ni(en) complexes are blue to green.

The Nien₃ salt is soluble in water producing a red-violet solution, auch bei grossen verdd.

[Ni en _n]²⁺ Ions (n = 1, 2 und 3). Stability constants for the stepwise Complex formation in aqueous solution.,

K _n = [Ni en _n]²⁺ /[Ni en _n-1]²⁺ [en] in liter mol-1

at various Ionic Strengths, I
"soweit nichts anderes vermerkt potentiometrisch ermittelt:"

{text uses lg for log; I'm reasonably sure that's log₁₀

	Temp.C	I	lg K1	lg K2	lg K3	Literature ref
	    0   0.5KNO3	7.92	6.77	5.36	1)
	    0.0	0	7.83	6.61	4.84	2)
	    0.0	0.15	7.88	6.70	4.78	3)
	   10.0	0	7.76	6.46	4.68	2)
	   10.0	0	7.74	6.44	4.67	4)
	   20.0	0	7.52	6.32	4.50	2)
	   20.0	0	7.52	6.32	4.49	4)
	  *25.0 0.1KNO37.52	6.28	4.26	5)
	   25.0	0.5 KNO37.60	6.48	5.03	1)
	   25.0	1 KNO3	7.54	6.39	4.39	6)
	   25.0	1 KNO3	7.51	6.35	4.42	7)
	   25.0	1 KNO3	7.61	6.39	4.35	8)
	   25.0	1 KC1	7.72	6.36	4.33	9)
	** 25.0 1.2 bis l.3NaClO4	
			7.55	6.20	4.77	10)
	   30.0	iKC1	7.66	6.40	4.55	11)
	   30.0	1 KCl	7.52	6.28	4.26	12)
	   30.0	1 KC1	7.45	6.23	4.34	13)
	   30.0	0	7.28	6.09	4.20	2)
	   30.0	0	7.27	6.11	4.20	4)
	   30.0	75 Vol.-% Dioxan
			8.2		-	14)
	   400	0	7.02	5.90	.1.98	2)
	   400	00	7.04	5.89	4.05	4)
	   49.1	0.15	6.92	5.75	3.90	3)
	   50.0	00	6.94	5.77	3.82	2)
*)	Nach polarograph. Unters. - * *) Spektrophotometrisch bestimmt.