From david at crystalmaker.com Fri Mar 9 16:05:59 2018 From: david at crystalmaker.com (David Palmer) Date: Fri, 9 Mar 2018 14:05:59 +0000 Subject: [Cod-bugs] Incorrect structure + spelling mistake - COD ID 1526591 Message-ID: Dear Sir/Madam, I recently came across a question about the crystal structure of the element gadolinium. One of our users had shown me a double-hexagonal-close-packed (?dhcp") structure, but Wyckoff claimed the element had a simple hcp structure. We took a look at your database and found that one of your structures appears to be incorrect. Here are the details:- COD ID: 1526591 There are two issues here:- 1. Spelling mistake in the journal title ?Supercondunctivity? (remove the second ?n?). 2. The structure makes no sense. - I don?t know whether some information has been lost here, but your CIF file lists only a single site, at {1/2, 1/2, 1/2} - which is a (very) special position. When plotted, this quite large unit cell only has this single atom - which is clearly incorrect. - If one is using an orthorhombic unit cell (for what is effectively an hexagonal lattice), then I would expect the ?a? or ?b? parameter to be much larger, something on the order of 6.3 ? (=2 . aH . cos(30), where ?aH? is the hexagonal parameter) - unless this is supposed to be some kind of derivative of the higher-temperature (?beta?) bcc lattice. I hope this information helps! With best wishes, David Palmer Managing Director, CrystalMaker Software Ltd CrystalMaker is a user-funded project to provide the very-best software for crystal and molecular structures modelling. We receive no EU subsidies, government bailouts, university salaries, pensions or student fee income. Everything we do is funded by our users - not the general taxpayer. It?s the only honest and sustainable way of providing quality software for the long term. -------------- next part -------------- An HTML attachment was scrubbed... URL: