This paper summarizes brief perspectives on the historic process of establishing an African Crystallographic Association (AfCA), including appropriate role players, organizations and accompanying events. It concludes with the official admission of AfCA as the fifth Regional Associate of the IUCr at the 26th Congress and General Assembly of the IUCr in Melbourne, Australia in 2023.

In the title coumarin derivative, the dihedral angle between the 2H-chromen-2-one ring system and the phenyl ring is 89.12 (5)°. In the crystal, the mol­ecules are linked by C—H⋯O hydrogen bonds into [010] double chains.

In the crystal, N—-H⋯O and O—H⋯O hydrogen bonds connect the two independent mol­ecules, forming (8) ring motifs. Weak C—H⋯O inter­actions link the mol­ecules, forming layers parallel to the (12) plane. The DMF solvent mol­ecules are also connected to the main mol­ecules N—H⋯O hydrogen bonds. π–π stacking inter­actions between the layers are also observed.

Dipotassium gadolinium(III) phosphate(V) molybdate(VI), synthesized from a high-temperature melt starting from GdF₃ as a source of gadolinium, has a structure that is isotypic with other M^I₂M^III(M^VIO₄)(PO₄) compounds, where M^I = Na, K or Cs, and M^III = rare-earth cation, M^VI = Mo or W. The three-dimensional framework is built up from [Gd(PO₄)(MoO₄)] anionic sheets, which are organized by adhesion of [GdPO₄] layers and [MoO₄] tetra­hedra stacked above and below of these layers, and the inter­stitial space is occupied by K cations having eightfold oxygen coordination.

The title compound, C₁₀H₁₁N₅O₂S₂, consists of an unexpected imino-di­hydro-triazine tautomer. Mol­ecules are linked by hydrogen bonds and by O_{sulf­on­amide}⋯(C—NH—C)_triazine contacts.

The synthesis and crystallographic analysis of [(E)-1,3-benzodioxol-5-yl­methyl­idene­amino]­thio­urea is reported, offering a comprehensive exploration of its structural features and supra­mol­ecular arrangements within the crystal.

The coordination polyhedron of the Cd²⁺ ion in the title compound is a CdN₂O₅ penta­gonal bipyramid formed by two bidentately coordinated carb­oxy­lic groups of different anions, one water mol­ecule and two pyridine mol­ecules. In the crystal, polymeric chains propagate along the [11] direction; the chains are linked by hydrogen bonds and π–π stacking inter­actions into a three-dimensional network.

In the title Schiff base tetra­nuclear copper(II) complex, two discrete environments are present in the structure: CuN₂OBr₂ and CuBr₄. Two copper(II) cations are situated in distorted square-based pyramidal environment, while two copper(II) cations are located in distorted tetra­hedral geometry.

In the crystal, mol­ecules of the title compound are linked into infinite sinusoidal chains along the [001] direction. The study demonstrated that dispersion energy was the most influential factor in the crystal organization of the compound.

The preparation and solid-state structures of three borylated ortho-silylaryl tri­fluoro­methane­sulfonates are reported. All compounds show the expected connectivity and unexceptional metric parameters as well as weak intra­molecular inter­actions.

In the title compound, the two hydrazide planes make a dihedral angle of 86.5 (2)°. In the crystal, C—H⋯O, N—H⋯O and N—H⋯N hydrogen bonds lead to the formation of a three-dimensional supra­molecular network.

The crystal structure of the title compound consists of discrete tetra­hedral complexes that are linked by weak inter­molecular hydrogen bonding. Upon heating, melting before decomposition is observed.

Five structures with methyl­piperidine ligands and gold(I) centres all exhibit linear geometry at the Au atom, and equatorial and axial positions, respectively, for the methyl groups and Au atoms at the piperidine rings. The packing involves hydrogen bonding and aurophilic inter­actions.

The title complex was synthesized by ligand metathesis from [1,3-bis­(2,6-diiso­propyl­phen­yl)imidazol-2-yl­idene]gold(I) chloride and sodium cyanate in anhydrous tetra­hydro­furan and crystallized from toluene at 233 K as a neutral complex with the central Au atom di-coordinated by an N-heterocyclic carbene and an iso­cyanate, with a linear CAuNCO moiety.

Single crystals of cubic alkali aluminoboracites A₄B₄Al₃O₁₂Cl (A = Li, Na) were grown from a self-flux and their crystal structures were determined and compared in two space group types, F3c and F23. Na₄B₄Al₃O₁₂Cl is the first sodium boracite and its lattice parameter is the largest among boracites with a cation–oxygen framework.

In the crystal structure of the title compounds, the Co^II cations are either sixfold or fivefold coordinated by two thio­cyanate anions and four or three 4-methyl­pyridine N-oxide coligands within a slightly distorted octa­hedral or a trigonal–bipyramidal coordination polyhedron.

The asymmetric unit of the title salt, Na⁺·C₆H₄BO₈⁻·H₂O, com­prises a five-coordinate sodium cation, a bis­(malonato)borate anion and a water mol­ecule of crystallization.

In the crystal of methyl 4-{2,2-di­chloro-1-[(E)-phenyl­diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯N hydrogen bonds, forming chains with C(6) motifs parallel to the b axis. In methyl 4-{2,2-di­chloro-1-[(E)-(4-methyl­phen­yl)diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯O hydrogen bonds and C—Cl⋯π inter­actions, forming layers parallel to (010). In methyl 4-{2,2-di­chloro-1-[(E)-(3,4-di­methyl­phen­yl)diazen­yl]ethen­yl}benzoate, mol­ecules are linked by C—H⋯π and C—Cl⋯π inter­actions, forming chains parallel to [011].

In the title crystal, mol­ecules are linked by N—H⋯O hydrogen bonds, forming ribbons parallel to (020) in zigzag C(7) chains along the a axis. These ribbons are connected via C—H⋯π inter­actions, forming a three-dimensional network.

A second polymorphic form of solvent-free miconazole, a triclinic form (MIC-tri), is reported, and compared with the anhydrous monoclinic form of miconazole (MIC-mono).

In the title com­pound, a benzyl­ideneaniline Schiff base, the planes of the p-substituted aromatic rings subtend a dihedral angle of 46.01 (6)°.

Cd₂(PO₄)OH and Cd₅(PO₄)₂(OH)₄ crystallize in the mineral structures of triplite and arsenoclasite, respectively.

The synthesis, crystal structure and analysis of a chiral Schiff base (S)-(+)-1-(4-bromo­phen­yl)-N-[(4-methoxyphen­yl)methyl­idene]ethyl­amine ligand along with its corresponding palladium(II) com­plex are detailed. The crystal structures exhibit monoclinic P2₁ and ortho­rhom­bic P2₁2₁2₁ symmetries, respectively. The structure of the palladium(II) com­plex reveals C—H⋯O and C—H⋯Br hydrogen-bonding inter­actions involving two distinct mol­ecules within the asymmetric unit.

In the title compound, C₂₇H₂₀N₄O₃S, the three aromatic rings are oriented almost perpendicular to the plane of the central 1,2,4-triazole ring.

In the crystal, mol­ecular pairs form dimers through N—H⋯O hydrogen bonds. These dimers are linked into ribbons parallel to the (100) plane by further N—H⋯O hydrogen bonds. In addition, π–π and C—Cl⋯π inter­actions between the ribbons form layers parallel to the (100) plane.

The crystal structure and thermogravimetric stability of [Pr₂(pydc)(phth)₂(H₂O)₃]·H₂O, a two-dimensional coordination polymer with a novel coordination mode of pyridine-2,5-di­carboxyl­ate (pydc²⁻), are reported.

In the crystal of 1-(4-methyl­benz­yl)in­do­line-2,3-dione, a layer structure is generated by C—H⋯O hydrogen bonds and C—H⋯π(ring), π-stacking and C=O⋯π(ring) inter­actions.