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Suspending crystals of bis(pentafluorophenyl)mercury [Hg(C6F5)2] (1a) in a saturated n-hexane solution for a prolonged period results in transformation into the new polymorph [Hg(C6F5)2] (1 b) monoclinic P21/n, a = 11.7060(3) ��, b = 7.8531(2) ��, c = 13.5429(4) ��, �� = 107.247(3)��, V = 1189.00(6) ��3. The C-Hg-C angle in 1 b is 177.10(11)�� and the pentafluorophenyl rings are rotated 74.6(1)�� to each other in comparison to 1a, the form known for 50+ years, which has a rotation angle of 58.0(2)��. Polymorph 1 b could also be obtained by crystallization from chloroform, or a CHCl3/n-hexane (1:1) mixture at ���20 ��C, or by seeding with a crystal of 1 b. Theoretical calculations suggest that the barrier to rotation is low.

The reaction of europium 8-quinolinolate Eu(OQ) 3 with calcium 8-quinolinolate, Ca(OQ) 2 , in the flux 1,2,4,5-tetramethylbenzene (TMB) at 210 °C yields the bimetallic [Eu 2 Ca(OQ) 8 ], which is a linear tri-nuclear complex with two eight coordinate europium atoms flanking a six coordinate calcium atom bonded by six bridging phenolate oxygen atoms. A similar reaction between La(OQ) 3 and Co(OQ) 2 gave [LaCo 2 (OQ) 7 ], in which two six coordinate cobalt atoms flank an eight coordinate lanthanum atom with six bridging phenolate oxygen atoms and a terminal OQ group.