A twofold rotation axis passes through the bridging O atom between the two sugar rings in the title compound, C₆₂H₆₂O₁₇. Otherwise the geometry is much as would be expected for this type of mol­ecule. Neither solvent nor hydrogen bonds are present in the crystal structure.

The structure of the title acid as the monohydrate, C₁₄H₁₈O₁₁·H₂O, displays hydrogen bonding which connects the mol­ecules in layers parallel to (10). In the anhydrous glucopyran­ose, C₁₄H₂₀O₁₀, only chain connectivity is attained but, due to disorder of the OH group, only partially and in two modes, one less favoured than the other. This provides incomplete connectivity between mol­ecules in corrugated layers parallel to (010).

Features of the structure of the title compound, C₂₈H₂₉BBrNO₂, are the planar coordination of B and the intramolecular BN contact distance of 3.204 (3) Å. The mol­ecules form layers parallel to (010), with the creation of π–π and C—Hπ contacts.

Tris(2-cyanoethyl)phosphine oxide, OP(C₂H₄CN)₃, C₉H₁₂N₃OP, is hexagonal (rhombohedral), space group R3c, with a = 13.484 (1) and c = 10.162 (1) Å. The sulphide and selenide are triclinic, space group P. Cell dimensions for SP(C₂H₄CN)₃, C₉H₁₂N₃PS, are a = 8.363 (8), b = 9.026 (4), c = 9.777 (6) Å; α = 98.75 (4), β = 107.31 (5), γ = 115.85 (5), and for SeP(C₂H₄CN)₃, C₉H₁₂N₃PSe, a = 8.497 (5), b = 9.148 (2), c = 9.972 (8) Å; α = 98.85 (2), β = 107.20 (6), γ = 116.96 (3)°. X-ray powder diffraction data are quoted.

Among the title compounds, viz. the acids C₁₀H₈ClF₂NO₃, (I), and C₁₁H₁₁F₂NO₃, (II), and the amides C₁₄H₁₄F₂N₂O₂, (III), and C₁₄H₁₃ClF₂N₂O₂, (IV), the change of substituent from Cl in (I) to methyl in (II) has a dramatic effect upon the hydrogen bonding between the mol­ecules, which occur in layers in both cases. In the structures of (III) and (IV), hydrogen bonds connect the mol­ecules to form chains, but the introduction of a chloro substituent in (IV) has a profound effect on the orientation of the mol­ecules within the chains and the packing of the chains in the structure as a whole.

The title compounds, di­chloro- and di­bromo­neophyl­phenyl­tin, [SnCl₂(C₆H₅)(C₁₀H₁₃)] and [SnBr₂(C₆H₅)(C₁₀H₁₃)], respectively, are remarkable for the `U' shape of the mol­ecules, whereby the two phenyl groups are brought face-to-face in an arrangement that permits intermolecular C—Hπ bonds to connect the mol­ecules into layers parallel to (100). Intermolecular Sn–halide bonds are notably absent from the structures.

The title compound, C₁₂H₇N₂O₂⁺·Br⁻ is, to our knowledge, the first reported example of a simple salt of cationic mono-N-protonated 1,10-phenanthroline-5,6-dione. All of the atoms lie on a crystallographic mirror plane and the cation is therefore totally planar. As a consequence, the compound has a well defined layer structure in which N—HBr, C—HBr and C—HO contacts within the layers interconnect the ionic species.

The asymmetric unit of the title compound, (Ph₄P)[Zn(C₃OS₄)₂], comprises six crystallographically independent entities, viz. two zincate anions and four counter-cations. Only the complex anions are of interest, noting in particular the tetrahedral coordination of the Zn atoms distorted primarily by the bite angles and asymmetric chelation of the ligands, and the non-linear nature of and departures from planarity in the anions themselves.

The title compound, (C₇H₁₀N)[Sb(C₆H₅)₂(C₃OS₄)₂], is a further example of a salt containing Sb^V of the form [Q][R₂Sb(dmio)₂], with Q an onium counter-cation and R = aryl. It is compared, particularly in terms of the packing of the ions in the unit cell, with other members of the series.

The title compounds, (C₁₆H₃₆N)₂[Sn(C₃OS₄)₃], (I), and (C₂₄H₂₀P)₂[Sn(C₃OS₄)₃], (II), are examples of complex salts of the general form [Q]₂[Sn(dmio)₃], where Q is ⁿBu₄N⁺ or Ph₄P⁺ and dmio is the 2-oxo-1,3-dithiole-4,5-dithiol­ate dianion. Features of both structures are the slightly distorted octahedral coordination of tin in the propeller-shaped dianions and the absence of any significant inter-anion contacts. The structure of (I) is particularly notable because all of the dianions in the sample crystal have the same propeller configuration, which is very unusual in this type of structure.