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Reaction of copper(II) chloride or bromide with 2-chloro-3-bromopyridine (2 or 2,3-dichloropyridine generates a family of compounds of the general formula L2CuX2 (1-4). X-Ray crystallography shows that the bromide complexes (3-bromo-2-chloropyridine)dibromidocopper(II) (1) and (2,3dichloropyridine)dibromidocopper(II) (3) are particularly unusual in that they crystallize with both the syn-and anti-conformation structures in the same crystal. A review of the literature on complexes of the formula (substituted-pyridine)2CuX2 suggests that these are the first examples of such complexes.The members of the family show a variety of magnetic behaviors and variable temperature magnetic susceptibility data indicate that 1 is essentially paramagnetic (θ = -0.9(1) K) while 3 is weakly ferromagnetic (J = 2.9(1) K). Compound 2 [(3-bromo-2-chloropyridine)dichloridocopper(II)] is well fit by the uniform one-dimensional antiferromagnetic model (J = -19.6(1) K), while compound 4 [(2,3-dichloropyridine)dichloridocopper(II) exhibits weak anti-ferromagnetic interactions (J = -3.68(3) K).

FORmany years, both in this country and abroad, lecturers on chemistry and textbook writers have illustrated their discussions of the important subjects of mass action and chemical equilibrium by showing the reversibility of the reaction between ferric chloride and ammonium thiocyanate in solution, usually represented by the equation FeCl3 + 3NH4CNS = Fe(CNS)s + 3NH.C1

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