Novel complexes possessing Hg–(Cl, Br, I)⋯O C halogen bonding and unusual Hg 2 S 2 (Br/I) 4 kernel. The usefulness of τ4′ structural parameter

Disappearing Polymorphs in Metal–Organic Framework Chemistry: Unexpected Stabilization of a Layered Polymorph over an Interpenetrated Three‐Dimensional Structure in Mercury Imidazolate

“…This value of τ 4 corresponds to a sawhorse geometry, slightly distorted toward a tetrahedral configuration. In this case, the low value of τ 4 ′ indicates that the effective coordination number of the metal may actually be higher than 4, a situation first noticed in a complex with Hg⋅⋅⋅π interactions . In the present case, additional short H⋅⋅⋅Hg contacts, described in more detail below, appear to fulfill this role.…”

Crystal structure of the [(THF)Cs(μ-η5:η5-Cp′)3Yb] n oligomer

“…Each ring bridges Yb to Cs, which also is surrounded by three cyclopentadienyl ligands as well as a coordinated molecule of THF. The three ring centroids and the oxygen of THF are arranged in a pseudo-tetrahedral geometry around Cs with a calculated four-coordinate Cs 0 4 value of 0.76 ( 0 4 = 1 for tetrahedral; 0 4 = 0 for square planar; Rosiak et al, 2018). The Cs metal center has a pseudo-tetrahedral geometry with Cp 0 (centroid)Á Á ÁCsÁ Á ÁCp 0 (centroid) angles of 109.0, 114.3, and 121.4 and Cp 0 (centroid)Á Á Á CsÁ Á ÁO(THF) angles of 88.8, 94.1, and 127.8 .…”

μ2-Chlorido-chlorido(μ2-4-{[2-(diethylamino)ethyl]imino}pent-2-en-2-olato)bis(tetrahydrofuran-κO)cobalt(II)lithium

“…1, Table 1). The corresponding 4 and 4 0 geometric parameters for four-coordinated central atoms (Yang et al, 2007;Okuniewski et al, 2015;Rosiak et al, 2018) are 0.86 and 0.85, respectively. They indicate that Li1 has a distorted tetrahedral coordination sphere ( 4 = 0 for an ideal square and 1 for an ideal tetrahedron).…”