The reaction between mercury(II)‐chloride and 2,6‐pyridinedimethanol provides a molecule with the empirical formula [Hg3(H2pdm)2‐(Hpdm) (μ‐Cl)2Cl3], whose crystal and molecular structure has been studied: a = 10.640(1), b = 10.818(2), c = 13.159(2) Å, α = 88.480(5), β = 75.067(4), γ = 89.736(5)°, V = 1463.0(4) Å3, Z = 2, P‐1. The molecule consists of a central [Hg(Hpdm)Cl] fragment that is connected by chloro bridges to twolateral fragments of identical constitution, [Hg‐(H2pdm)Cl2]. The coordination geometry around the central mercury atom is distorted octahedral, while the lateral metal atoms are located in significantly different, distorted square‐pyramidal polyhedrons. The tridentate ligand induces the formation of the square‐pyramidal environment instead of the trigonal‐bipyramidal one that is normally preferred by d10 systems. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:377–382, 1998