Low-temperature KFeGeO₄

Low-temperature potassium iron germanium tetraoxide is a stuffed tridymite derivative with a completely disordered Fe/Ge tetrahedral distribution.

Hexagonal β-KFeSiO₄

The low-temperature β-KFeSiO₄ (potassium iron silicate) polymorph crystallizes with a kalsilite-type structure having P6₃22 symmetry and a disordered Fe/Si tetrahedral distribution.

1,1-Bis(4-methoxyphenyl)-3,3-di­methylbutan-2-one

The title compound was obtained as a by-product of the reaction of pinacolone and 4-iodoanisole. The crystal structure was determined at 120(2)K. The molecule is bisected by a mirror plane (space group Pnma).

Ethyl hydrogen 4,5-di­bromophthalate

The molecular structure of 4,5-dibromophthalic acid monoethyl ester is normal. The carboxylic acid group is rotated 12.8° and the ethoxycarbonyl group 69.0° out of the mean plane of the benzene ring.

1-De­oxy-1-(2-fluoro­phenyl)-β-D-ribo­furanose

The ribofuranose ring in the title compound has a C2^'-endo envelope conformation. The crystal packing consists of intermolecular hydrogen-bonding and phenyl⋯phenyl interactions.

1-De­oxy-1-(3-fluoro­phenyl)-β-D-ribo­furanose

The structure of the title compound is isostructural with 1-deoxy-1-phenyl-β-D-ribofuranose [Matulic-Adamic et al. (1996). J. Org. Chem. 61, 3909–3911]. The ribofuranose ring has a C2^'-endo,C3^'-exo twist conformation.

Methyl 2-amino-4-(methoxymethyl)thiazole-5-carboxylate

The two crystallographically independent conformations of the title compound differ only by the rotational positions adopted by their methoxymethyl substituents. Intermolecular contacts are dominated by hydrogen bonding involving the amine H atoms.

A diketopiperazine derivative of quinapril

The title compound, ethyl 2-(1,2,3,4,5,6,11,11a-octahydro-3- methyl-1\,4-dioxopyrazino[1\,2-b]isoquinolin-2-yl)-4-phenylbutanoate, is formed due to cyclization of quinapril in solution. The configurations at the three chiral centres are all S. The six-membered B and C rings assume half-chair and boat confirmations, respectively. The molecules in the lattice are stabilized by van der Waals contacts.

8-Methyltri­cyclo[9.3.0.0^3,7]tetradec-3-ene-5,10-dione and 7,12-di­hydroxy-9,12-di­methyltetra­cyclo[8.2.1.0^1,5.0^7,11]tridecan-13-one methanol solvate

The title compounds, C₁₅H₂₀O₂, (I), and C₁₅H₂₂O₃^.CH₃OH, (II), were obtained by intramolecular cyclization of the 5- and 3-acetonyl derivatives of 4-methylbicyclo[6.3.0]undecane-2,6-dione, respectively. Dione (I) is an ophiobilin-like C₅–C₈–C₅ fused-ring compound and diol (II) is a C₅–C₆–C₅–C₅ tetracyclic compound.

Redetermination of bi­phenylene at 130K

Biphenylene is one of the key compounds in the discussion of bond localization in aromatic systems, usually addressed as the Mills–Nixon effect [Mills & Nixon (1930). J. Chem. Soc. p. 2510]. A pronounced bond localization due to the Mills–Nixon effect in the direction of one of the Kekule forms is established. Compared with the previous structure determination by Fawcett & Trotter [Acta Cryst. (1966), 20, 87-93], the significance of bond-length alternation in relation to the s.u.'s in the six-membered rings has been dramatically increased.

1,4,4a,5,8,8a-Hexa­hydro-1,4-methano­naphthalene-5,8-dione

The title compound crystallizes with two nearly identical molecules in the asymmetric unit. The molecules essentially exhibit mirror symmetry.

Substituted clonidine derivatives. I. 3,5-Di­chloro-4-(imidazolidin-2-yl­idene­amino)benzo­nitrile and 3,5-di­chloro-4-(1,3-diisobutyrylimidazolidin-2-yl­idene­amino)benzo­nitrile

In the title compounds, C₁₀H₈C₁₂N₄ (R= H), (I), and C₁₈H₂₀C₁₂N₄O₂ (R = COCHMe₂), (II), the dihedral angle between the imidazolidine and phenyl rings are 67.7(1) and 70.34(9)°, respectively. In (I), the imidazolidine ring adopts a half-chair conformation, whereas in (II), it is in a flattened envelope conformation.

A Ruddlesden–Popper-type layered perovskite, Na₂Ca₂Nb₄O₁₃

The structure of Na₂Ca₂Nb₄O₁₃ consists of perovskite-type layers with a thickness corresponding to four perovskite cubes. The interlayer structure is of the rock-salt-type, composed of Na and O atoms. The atomic configuration suggests a ferroelectric nature along the b axis.

Pentabarium tetra­antimonide, β-Ba₅Sb₄: a more symmetrical arrangement for the Ba₅Sb₄ compound

β-Ba₅Sb₄ displays a more symmetrical arrangement than α-Ba₅Sb₄ (Pnma). It contains two anionic moieties, Sb₂⁴⁻ and Sb³⁻, lying in tricapped and distorted monocapped trigonal prisms of Ba atoms, respectively.

K₂TeS₃

The reaction of K₂S₃, tellurium and sulfur yields light-yellow single crystals of dipotassium tellurium trisulfide, K₂TeS₃. The structure consists of isolated TeS₃²⁻ anions, and K⁺ cations coordinated by six S atoms from five different TeS₃²⁻ anions within distorted octahedra.

A potassium sodium double salt of metavanadate, KNa(VO₃)₂

KNa(VO₃)₂ adopts the pyroxene structure with K⁺ and Na⁺ cations, which lie on twofold axes, occupying the dodecahedral and octahedral cavities, respectively.

Penta­carbonyl-1κ⁴C,2κC-[2(η⁵)-cyclo­pentadienyl]-μ-di­cyclo­hexylphosphido-1:2κ²P-manganeserhodium(Mn–-Rh)

[2,6-Bis(N-tert-butylimino­methyl)pyridine-κ³N](phenolato-κO)rhodium(I)

A hydrated diclofenac salt of the hexa­aquamagnesium ion

trans-Bis(acetato-O)bis­(2-amino-6-methylpyridine-N)copper(II)

Di-μ-chloro-bis­(aqua­chlorodi­methyltin)–di­chlorodi­methyl[2,4,6-tris­(2-pyridyl)-1,3,5-triazine]tin (1/2)

A nickel complex with a tetradentate N₂S₂ Schiff base ligand

(5,6-Di­methyl-1,10-phenanthroline)(nitrato)(salicylaldehydato)copper(II)

Aqua(4,7-di­phenyl-1,10-phenanthroline)(salicylaldehydato)copper(II) nitrate monohydrate

Tetra­kis­(μ-phenylacetato-O:O')bis­[(quinoline-N)cobalt(II)]

Charge-transfer salt of bis­(cis-1,2-di­phenylethene-1,2-di­thiolato)palladate(1 –) with cobaltocenium, and neutral bis­(cis-1,2-di­phenylethene-1,2-di­thiolato)palladium

A linear trinuclear Cd^II–Cd^II–Cd^II complex with a μ-acetato bridge: bis­{(μ-acetato)[μ-bis­(salicyl­idene)-1,3-propanediaminato]cadmium(II)}cadmium(II)

Three anionic polymeric networks: sodium(I)–ruthenium(III), sodium(I)–rhodium(III) and sodium(I)–aluminium(III) μ-oxalato complexes with tris­(2,2'-bi­pyridine)ruthenium(II) cations

Intermolecular (pyrrole)N—H⋯π(pyrrole) interactions in bis­(2-pyrrolyl)methylferrocene, an organometallic porphyrin precursor

exo-[(RS,SR)-N,N'-Bis(salicyl­idene)-2,3-butanediaminato]oxovanadium(IV)

Di-μ-aqua-bis­[(tri­methanol-O)sodium] anti-bis­(μ-2-propane­thiolato-S:S)bis­[bis­(2-propane­thiolato-S)iron(II)] and bis­(benzyltri­methylammonium) anti-bis­(μ-2-propane­selenolato-Se:Se)bis­[bis­(2-propane­selenolato-Se)iron(II)]

Di­aquabis(2,2'-bi­pyridine-N,N')nickel(II) diperchlorate

Chloro(penta­methyl-η⁵-cyclo­pentadienyl)bis­(tri­phenylphosphine)ruthenium(II)

A copper(I) complex of 4-amino-3-thioxo-6-methyl-2,3,4,5-tetra­hydro-1,2,4-triazin-5-one

(R)-Spiro[(2R)-N-acetyl-2-phenyl-1,3-thiazolidine-4,3'-(3a'R,6a'S)-5',6a'-di­methyl-3a',-6a'-di­hydro-3H-furo[2,3-b]furan-2-one]

N,N'-Di­phenylguanidinium di­hydrogen phosphate

3,12-Di­aza-6,9-diazoniadi­spiro[5.2.5.2]hexa­decane dichloride from X-ray powder data

6-(2-Nitroprop-2-yl)quinoline-5-carbo­nitrile

4,6,7,8,8a,9-Hexa­hydrothieno[3,2-f]indolizine-6,9-dione

Molecular aggregation in selected crystalline 1:1 complexes of hydrophobic D- and L-amino acids. II. The D-norleucine series

A 1:1 complex between deoxycholate and tris­(hydroxymethyl)methylammonium

3,5-Di­chloro-4-(imidazolidin-2-yl­idene­ammonio)benzoate dihydrate

(8RS,5SR,7SR)-7-Benzoyl-8-hy­droxy-8-phenylspiro[4.5]decan-1-one

3-Cyclo­propyl-1,2,4-triazolo[3,4-b]benzo­thiazole monohydrate

Tetra­ethylammonium (N,N-di­ethyldi­thiocarbamato-S,S')tetra­iodotellurate(IV)

2,2-Bis(2-methoxyphenyl)-4-methyl-2H-benzo[h]chromene

9-Hy­droxy-4-methyl-8-phenylthio-7,8,9,10-tetra­hydrobenzo[h]coumarin

Methyl (2RS,4aRS,8aRS)-2-(4-methylbenzyl)-3-oxoperhydro­naphthalene-2-carboxylate

4,4a,4b,5,6,7,9,9a-Octa­hydro-1,4-methano-7-methyl-5-nitro-1H-fluoren-9-one

(2RS,5RS)-2,5-Bis[3-(4-methylphenyl)-3-oxo­propyl]cyclo­pentan-1-one

1-(4-Benzylpiperidin-1-yl)glyoxal dioxime

9a-Propargyl-1,2,3,9-tetra­hydrofluorene-3,9-dione

4-(4-Methylphenyl)-3-phenyl-4H-1,2,4-triazole

Methyl (5SR,6SR)-1,3-di­chloro-8-di­ethylamino-5,6-di­hydro-5-hy­droxy-7-nitro-6-phenyliso­quinoline-5-carboxylate

Tri­methyl (5SR,6SR)-1,3-di­chloro-8-di­ethylamino-5,6-di­hydro-5-hydroxyiso­quinoline-5,6,7-tri­carboxylate

Imidazole-4-acetic acid monohydrate

An asatone-type neolignan and its photocage product

Diiso­propylammonium di­phenylmethylnitronate at 200K

Pyridinium and 1,2-diazinium salts of chloranilic acid

7-Iodo-3-iso­propylamino-4H-1,2,4-benzo­thiadiazine 1,1-dioxide

(Z)-N-Benzyl-2,3-di­hydro-2-(2-methoxybenzyl­idene)-4H-1,4-benzoxazine

Tris(prop-2-ynyl)ammonium chloride

(+/-)-(3'aα,4'α,6'aα)-3',3'a,4',6'a-Tetra­hydro-5,5,N,N-tetra­methylspiro[1,3-dioxane-2,2'(1'H)-pentalene]-4'-acetamide, a triclinic crystal structure with local monoclinic pseudosymmetry

4-(1H-1,2,4-Triazol-1-yl)phenol

(2-Hydroxyethyl)diiso­propylammonium chloride and its derivatives

(1S,2R)-1-Amino-2-methoxycyclo­hexane-1-carboxamide hydrochloride 0.25-hydrate

Mixed stacking and stoichiometry in a π-molecular complex between fluorene and 1,3,5-tri­nitro­benzene

Bis(2,2-di­methylaziridinyl)phosphinic amide

2,2'-Ethylene­dioxydibenzaldehyde bis­(thiosemicarbazone) bis­(di­methyl sulfoxide)

Hydrogen bonding and C—H⋯O interactions in 2,2'-di­hydroxy-5,5'-di­methoxybi­phenyl-3,3'-dicarbaldehyde

1,2:3,4:5,6-Tri-O-iso­propyl­idene-D-mannitol

6-Chloro-1-(α-chloro­acetyl)-1,2,3,4-tetra­hydro-4-methylquinoline-2-spiro­cyclo­hexane

Low-temperature phase of bis­(2-methoxycarbonyl-2-methylpropyl) 2,5-diiso­propyl­idene-3,4-bis­(2-methoxycarbonyl-2-methylpropoxycarbonyl)hex-3-enedioate, a crystal structure with six independent pseudo-related molecules

17-Oxo-17a-oxa-17a-homo-5α-androstan-3α,4β-diyl di­acetate

Racemic 3-(3,4-di­methoxyphenyl)-5a,6,8,9-tetra­hydro-1H,7H-pyrano[4,3-b][1]benzo­pyran-1-one, an active antitumor agent

2-(Iso­propylthio)benzoic acid

Hydrogen bonding in quinolinium-4-carboxylate trihydrate

N,N',N''-Tri­methyl-N,N',N''-tris­(3-methylphenyl)-1,3,5-benzenetricarboxamide is cubic (space group Pa) and not orthorhombic (space group Pbca). Erratum