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An erratum to the paper by Miyakawa et al. [(2007), Acta Cryst. F63, 737–739].

A correction is made to one of the affiliations of the authors and also to a table heading in Miyakawa et al. (2007), Acta Cryst. F63, 737–739.

Erratum to Livet [Acta Cryst. (2007), A63, 63–87].

In the paper by Livet [Acta Cryst. (2007), A63, 63–87], equation (15) is incorrect. The correct equation is

The title compound, [Cu(CH3CN)(C12H12N2)2](BF4)2, crystallizes with two copper-containing cations and four tetra­fluoro­borate anions in the asymmetric unit. The structure represents a second crystal form of the salt, the first being an acetonitrile solvate [Watton (2009 ▶). Acta Cryst. E65, m585–m586]. The complex cation has a distorted trigonal-bipyramidal geometry, whereas the previous structure exhibits a distorted square-pyramidal geometry. One of the four BF4 − counter-ions is disordered, with a refined site occupancy of 0.8615 (17):0.1385 (17).

An erratum to the paper by Inagaki et al. [(2006), Acta Cryst. F62, 169–171].

An error is corrected in the paper by Inagaki et al. [(2006), Acta Cryst. F62, 169–171].

Corrigendum to Acta Cryst. (2009), E65, o610–o611.

The chemical name of the title compound in the paper by Jenkinson, Fenton, Booth, Fleet & Watkin [Acta Cryst. (2009), E65, o610–o611] is corrected.

Corrigendum to Acta Cryst. (2007), E63, o2296.

In the paper by Hong, Song & Wu [Acta Cryst. (2007), E63, o2296], the scheme shows the wrong structure. The correct scheme is shown below and the compound name is corrected to "poly[[di-μ2-aqua-diaqua-hemi-μ6-oxalato-barium(II)] 2,4,6-trinitro­phenolate monohydrate", {[Ba(C2O4)0.5(H2O)4]C6H2N3O7·H2O}n.

Corrigendum to Acta Cryst. (2007), E63, m2329.

An error in the original formulation of the title compound in the paper by Sadiq-ur-Rehman, Sherzaman, Ali, Shahzadi & Helliwell [Acta Cryst. (2007), E63, m2329] is corrected.The title compound in the paper by Sadiq-ur-Rehman, Sherzaman, Ali, Shahzadi & Helliwell [Acta Cryst. (2007), E63, m2329] was an unexpected product which seemed to have nitrate coordinated to three Sn atoms. However, it was noticed that the charges do not balance and that it is most likely that the nitrate is in fact a carbonate. Regrettably, there is no material to carry out microanalysis, but a plausible mechanism has been suggested to explain the unexpected formation of the product. Trimethyl­tin chloride will react with methanol in the presence of a base (4-hydroxy­piperidine) to give trimethyl­tin methoxide, which will rapidly hydrolyze in air to give the hydroxide. Both the methoxide and the hydroxide will react with atmospheric CO2 to give the carbonate (Bloodworth et al., 1967 ▶; Blunden et al., 1984 ▶; Sato, 1967 ▶). Me3SnCl + MeOH + base → Me3SnOMe + base·HCl Me3SnOMe + H2O → Me3SnOH + MeOH Me3SnOH + CO2 → Me3SnOCO2HMe3SnOCO2H + Me3SnOMe → Me3SnOCO2SnMe3 + MeOH. The carbonate then forms a coordination copolymer with trimethyl­tin chloride. The name of the title compound is corrected to poly[μ3-carbonato-μ3-chlorido-nona­methyl­tri­tin(IV)], [Sn3(CH3)9(CO3)Cl] (M r = 586.84).

Corrigenda to Acta Cryst. (2007), E63, o4363, o4364, o4434–o4435, o4436–o4437, o4438, o4489–o4490 and o4491–o4492.

Corrections are made to the name of an author in seven papers by Chinnakali et al. [Acta Cryst. (2007), E63, o4363, o4364, o4434–o4435, o4436–o4437, o4438, o4489–o4490 and o4491–o4492].

Corrigendum to Acta Cryst. (2007), E63, o4725.

The chemical name in the title of the paper by Chakkara­varthi, Anthonysamy, Balasubramanian & Manivannan [Acta Cryst. (2007), E63, o4725] is corrected.

Corrigendum to Acta Cryst. (2007), E63, o1210–o1211.

The list of authors in the paper by Sun, Chen, Ling & Liu [Acta Cryst. (2007), E63, o1210–o1211] is corrected.

Corrigendum to Acta Cryst. (2007), E63, o4654.

The title and the chemical diagram of the paper by Kang, Li, Zeng, Wang & Wang [Acta Cryst. (2007), E63, o4654] are corrected.

Corrigendum to Acta Cryst. (2007), E63, o3999.

The name of the first author in the paper by Chen & Cao [Acta Cryst. (2007), E63, o3999] is corrected.

Corrigendum to Acta Cryst. (2007), E63, m2975–m2976.

The chemical formula in the paper by Wojciechowska & Daszkiewicz [Acta Cryst. (2007), E63, m2975–m2976] is corrected.

Corrigendum to Acta Cryst. (2007), E63, i194.

The title and formula in the paper by Zhou et al. [Acta Cryst. (2007), E63, i194] are corrected.

The accuracy of a dispersion-corrected density functional theory method is validated against 241 experimental organic crystal structures from Acta Cryst. Section E.

This paper describes the validation of a dispersion-corrected density functional theory (d-DFT) method for the purpose of assessing the correctness of experimental organic crystal structures and enhancing the information content of purely experimental data. 241 experimental organic crystal structures from the August 2008 issue of Acta Cryst. Section E were energy-minimized in full, including unit-cell parameters. The differences between the experimental and the minimized crystal structures were subjected to statistical analysis. The r.m.s. Cartesian displacement excluding H atoms upon energy minimization with flexible unit-cell parameters is selected as a pertinent indicator of the correctness of a crystal structure. All 241 experimental crystal structures are reproduced very well: the average r.m.s. Cartesian displacement for the 241 crystal structures, including 16 disordered structures, is only 0.095 Å (0.084 Å for the 225 ordered structures). R.m.s. Cartesian displacements above 0.25 Å either indicate incorrect experimental crystal structures or reveal interesting structural features such as exceptionally large temperature effects, incorrectly modelled disorder or symmetry breaking H atoms. After validation, the method is applied to nine examples that are known to be ambiguous or subtly incorrect.

A correction to the paper by Asojo et al. [(2005), Acta Cryst. F61, 391–394].

Data collection and instrument information reported in the article by Asojo et al. [(2005), Acta Cryst. F61, 391–394] are corrected.

Corrigendum to Acta Cryst. (2009), E65, o846.

The chemical name of the title compound in the paper by Xu, Huang & Guo [Acta Cryst. (2009), E65, o846] is corrected and the structural diagram is updated.

Corrigendum to Acta Cryst. (2004), E60, o117–o119.

The chemical name of the title compound in the paper by Devi, Malathi, Rajan, Aravind, Krishnakumari & Ravikumar [Acta Cryst. (2004), E60, o117–o119] is corrected and the structural diagram is updated.

Corrigendum to Acta Cryst. (2009), E65, o392.

The chemical name of the title compound in the paper by Hu & Wang [Acta Cryst. (2009), E65, o392] is corrected and the structural diagram is updated.

Corrigendum to Acta Cryst. (2009), E65, o262.

The chemical name of the title compound in the paper by Sun, Li, Wang, Fu & Wang [Acta Cryst. (2009), E65, o262] is corrected and the structural diagram is updated.

The crystal structure of the title compound [systematic name: 5,6,10-trihydr­oxy-7-isopropyl-1,1,4a-trimethyl-2,3,4,4a-tetra­hydro­phenanthren-9(1H)-one], C20H26O4, has been reported previously [Salae et al. (2009 ▶). Acta Cryst. E65, o2379–o2380], but the absolute configuration could not be determined as there was no significant anomalous dispersion using data collected with Mo radiation. The absolute configuration has now been determined by refinement of the Flack parameter with data collected using Cu radiation. The absolute configuration at position 4a of the diterpenoid is (R)-methyl; other features of the mol­ecule and its crystal packing are similar to those previously described.

The title compound, sodium tetraborate decahydrate (mineral name: borax), Na2[B4O5(OH)4]·8H2O, has been studied previously using X-ray [Morimoto (1956). Miner. J. 2, 1–18] and neutron [Levy & Lisensky (1978). Acta Cryst. B34, 3502–3510] diffraction data. The structure contains tetra­borate anions [B4O5(OH)4]2− with twofold rotation symmetry, which form hydrogen-bonded chains, and [Na(H2O)6] octa­hedra that form zigzag chains [Na(H2O)4/2(H2O)2/1]. The O—H bond distances obtained from the present redetermination at 145 K are shorter than those in the neutron study by an average of 0.127 (19) Å.

Corrigenda for five articles.

The affiliation of one of the authors and a source of funding are both added in the following papers: Chiririwa & Meijboom [Acta Cryst. (2011a), E67, m1496; Acta Cryst. (2011b), E67, m1497; Acta Cryst. (2011c), E67, m1498] and Chiririwa & Muller [Acta Cryst. (2012a), E68, m49; Acta Cryst. (2012b), E68, m116–m117].

Corrigendum to Acta Cryst. (2007), E63, o4446.

Corrections are made to the name of the author and the address in Zhong [Acta Cryst. (2007), E63, o4446].

Corrigendum to Acta Cryst. (2007), E63, m1783–m1784.

Corrections are made to the formulation and scheme in Tombul, Güven & Büyükgüngör [Acta Cryst. (2007) E63, m1783–m1784].