The life and career of Jerry P. Jasinski are celebrated in a virtual special issue.

Knowledge of space groups and the implications of space group symmetry on the physical and chemical properties of solids are pivotal factors in all areas of structural science. The tutorial contains > 200 PowerPoint `slides', in five modules, arranged by crystal class; a sixth module covers special topics. A `credits' module gives the direct addresses of all embedded links. In the tutorial, lattice points build iteratively and inter­actively with keyclick, and the coordinates of points `pop up' as the unit cell is filled.

`Symmetry and Space Group Tutorial' (by Jerry P. Jasinski and Bruce M. Foxman) provides chemistry students an opportunity to learn space-group diagrams through the peer-tutoring approach.

Two crystallographically independent mol­ecules are present in the asymmetric unit. O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds form rings and chains and π–π stacks further connect mol­ecules in the crystal.

[Rh(μ-I)(COD)]₂ was found to crystallize as two different polymorphs in which the Rh dimer adopts either bent or planar geometries with respect to the Rh₂I₂ core.

The unsubstituted cyclo­penta­dienyl ring is rotationally disordered while the other Cp ring and its substituent are close to coplanar. In the crystal, the mol­ecules pack in `bilayers' parallel to the ab plane with the ferrocenyl groups on the outer faces and the substituents directed towards the regions between them. The ferrocenyl groups are linked by C—H⋯π(ring) inter­actions.

Five new bis­(aryl­amide)­dichlorido­zinc(II) complexes have been prepared and characterized. All of the complexes contain hydrogen bonds between the amide N—H group and the amide carbonyl oxygen atoms or the chlorine atoms, forming extended networks.

The reported mol­ecule contains a number of unusual features, the most notable being a finite yet exceptionally long cyclic metal-azido chain. These rare features are the consequence of both sterically protecting Cp* ligands and highly bridging oxide and hydroxide ligands in the same system and illustrate the inter­esting new possibilities that can arise from combining organometallic and solvothermal f-block element chemistry.

(E)-1-(4-Meth­oxy­phen­yl)-3-[4-(prop-2-yn­yloxy)phen­yl]prop-2-en-1-one undergoes a cyclo­condensation reaction with thio­semicarbazide to form the corresponding 4,5-di­hydro­pyrazole-1-arbo­thio­amide, which in turn undergoes further cyclo­addition with phenacyl bromides to form 4,5-di­hydro-1-(thia­zol-2-yl)pyrazoles. The mol­ecules adopt an overall T-shape structure. Different combinations of hydrogen bonds link the mol­ecules into ribbons or sheets.

The crystal structures of two manganese(II) complexes have been determined. The manganese(II) centers of each structure are six-coordinate with a distorted octa­hedral geometry. Although the bis­(quinolin-2-ylmeth­yl)ethanamine ligands differ only by a methyl group, the structure of one complex is dimeric with bridging acetate ligands and exhibits a trans coordination and coplanarity of the quinolyl moieties, while the second complex is monomeric with a cis coordination of the quinolyl groups.

A hydrogen sulfate salt, [BnSeCH₂CH(Ph)NH₃⁺](HSO₄⁻), of a chiral selenated amine (R)-2-(benzyl­selan­yl)-1-phenyl­ethanamine (BnSeCH₂CH(Ph)NH₂) has been synthesized and characterized by elemental analysis,¹H and ¹³C{¹H} NMR, FT–IR analysis, and single-crystal X-ray diffraction studies. This selenated salt crystallizes as a monohydrate. In the crystal, several O—H⋯O and N—H⋯O hydrogen bonds and C–H⋯π and Se⋯O weak inter­actions result in a complex two-dimensional sheet-like supra­molecular architecture.

The structures of 1:1 and 1:2 adducts of phosphanetricarbo­nitrile with 1,4-di­aza­bicyclo­[2.2.2]octane are reported.

The metallamacrocyclic core of the discrete hexa­nuclear 15-metallacrown-5 complex [TbCu₅(GlyHA)₅(H₂O)_6.5(SO₄)]₂(SO₄)·6H₂O contains five copper(II) ions linked by five glycine­hydroxamate (GlyHA^2–) dianions with a square-anti­prismatically octa­coordinate terbium(III) ion in the centre. The positive charge of the 15-metallacrown-5 [TbCu₅(GlyHA)₅]³⁺ core is compensated by bidentate and non-coordinated sulfate anions.

The X-ray crystal and mol­ecular structures, DFT study and Hirshfeld surface analysis of a novel spiro­bicyclic diselenide are reported.

A tetra­nuclear complex with an open-cubane like structure was synthesized from 2-meth­oxy-6-(pyridin-2-yl-hydrazonometh­yl)-phenol and characterized using micro-analytical and spectroscopic techniques, and single-crystal X-ray diffraction analysis.

The title Eu complex, featuring both Anthracac and tris­pyrazolyl­hydro­borato ligands, exhibits an octa­vertex square-pyramidal coordination environment.

A cobalt sulfate complex supported by β-picoline ligands produces a unique cuboidal tetra­mer.

With cobalt(II) chloride, some piperazine- and homo-piperazine-derived ligands yield tetra- or penta­coordinate complexes. Observed variations in coordination number are ascribed as being related to chloride solvophobicity. Optical spectra are presented, while magnetism measurements indicate governance of the magnetism by zero-field splitting of the cobalt ion.

The reaction of [Cu(CH₃CN)₄](BF₄) with 1-methyl-1,3-imidazolidine-2-thione {SC₃H₄(NMe) NH} forms the one-dimensional coordination polymer [Cu₄(κ⁵:L¹—N—S—N—L¹)₂(κ¹:L¹—NH)₂(κ²: L¹—NH)₂]_n(BF₄)_4n {L¹ = SC₃H₄(NMe)NH} with sulfur-bridged {Cu^I₄S₁₀}_n central cores.