title: Some errors from the crystallographic literature, some amplifications and a questionable result.
abstract: The space groups of [[Mo(2)(O(2)CCH(3))(4)('linker')](n)] are corrected from P1 to C2/m for 'linker' = pyrazine and 1,4-diazabicyclo[2.2.2]octane (dabco) and from P1 to C2/c for 'linker' = 4,4'-bipyridine. Also, [[tris-(2-pyridylmethyl)amine]BrV(mu-O)VBr[tris-(2-pyridylmethyl)amine]]Br.H(2)O is corrected from P1 to C2/c. These Laue class changes allow more reliable crystallochemical comparisons to be made among families of related structures. Space groups are corrected for 4-methyl-2,6-bis(4-methylbenzylidene)cyclohexanone, 2,6-bis(4-dimethylaminobenzylidene)cyclohexanone, K[Cr(tetramethylenediamine-N,N,N',N'-tetraacetate)].H(2)O and [bis(11,-11-dimethyl-3,4:8,9-dibenzobicyclo[4.4.1]undeca-3,8-diene)-(tetracyanoethylene)]. The conflicting reports for Cu(H(2)O)-(phenanthroline)(2)(X)(2), where X = ClO(4), NO(3) and BF(4), are resolved. Three related examples of open framework host-guest structures with space groups 'Cc or C2/c' are discussed. Adding centers to 2,2'-bi-1H-imidazolium dipicrate and [tris(2,2'-bi-1H-imidazole)bis[2-(2-1H-imidazolyl)-1H-imidazolium]bis(iodide)] corrects discrepancies of up to 0.38 A between chemically similar hydrogen-bond distances. Wrongly identified atoms are corrected in theta-[bis(ethylenedithio)tetrathiafulvalene](2) (CsCd)(SCN)(4) and (purported) diaquadihydroxotetrakis(m-nitrobenzenesulfonate)discandium(III). The reported difference between the crystal structure of (CH(3)NH(3))(4)YbCl(7) and those of the other members of this family of (CH(3)NH(3))(4)MX(7) (M = In, Fe, V; X = Cl, Br) structures is pointed out in the context of possibly different N-H...Cl hydrogen bonding in the Yb structure.