[Cod-bugs] Invalid CIFs for LiNbO3

[David Palmer]

Dear Sir/Madam,

The following CIF entries for LiNbO3 are invalid:-

2101176 - 2101185

These files violate the CIF standard by failing to include any general-equivalent positions - as is required in the CIF file specification. Instead, the files simply give a vague spacegroup symbol (NOTE: there is no agreed syntax for plain-text spacegroup symbols, so authors should NEVER rely on a plain-text spacegroup string in a CIF file.)

For reference, the missing general equivalent positions would be as given in the following output from CrystalMaker X (*):-

loop_
_symmetry_equiv_pos_as_xyz
'+x,+y,+z'
'-y,+x-y,+z'
'-x+y,-x,+z'
'-y,-x,1/2+z'
'-x+y,+y,1/2+z'
'+x,+x-y,1/2+z'
'2/3+x,1/3+y,1/3+z'
'1/3+x,2/3+y,2/3+z'
'2/3-y,1/3+x-y,1/3+z'
'1/3-y,2/3+x-y,2/3+z'
'2/3-x+y,1/3-x,1/3+z'
'1/3-x+y,2/3-x,2/3+z'
'2/3-y,1/3-x,5/6+z'
'1/3-y,2/3-x,1/6+z'
'2/3-x+y,1/3+y,5/6+z'
'1/3-x+y,2/3+y,1/6+z'
'2/3+x,1/3+x-y,5/6+z'
'1/3+x,2/3+x-y,1/6+z'

I hope this helps.

Best wishes,

David Palmer


(*) CrystalMaker X is a user-funded project to develop the world’s best software for crystal and molecular structures. We receive no government funding, salaries, research grants or external sponsorship: all our software is funded by our users. Pure, transparent, honest. The only viable option for long-term development and support.