View CIF files in your browser
Crystallography's own format, for a mineral's or a medicine's crystal and, as mmCIF, every structure in the Protein Data Bank. Open one right here in 3D. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your molecule opens in 3D, a protein's chains as a cartoon and a small molecule's atoms as balls and sticks, with its parts beside it and what you pick on the other side.
- Turn, zoom and move it • Double click to center on a point
- Cartoon, balls and sticks or spacefill • By element, chain or residue
- Inspect an atom • Its residue, chain, charge and B-factor
- Export • PNG, GLB, USDZ, STL and OBJ
About CIF
The International Union of Crystallography made CIF in 1991 so crystal structures could be handed in with papers, and journals like Acta Crystallographica and databases like the Cambridge Structural Database and the Crystallography Open Database keep them as CIF. Its kin mmCIF, or PDBx/mmCIF, has been the Protein Data Bank's own format since 2014.
A CIF is text of named items, like _cell_length_a, and loops of rows. A crystal's CIF gives its cell's lengths and angles, its space group's symmetry and the atoms of its asymmetric unit as fractions of the cell, and an mmCIF lists every atom of a structure with its residue, chain and place in Å.
Filepeek reads both in your browser. A crystal opens as its unit cell filled with every atom its symmetry places, each molecule kept whole, inside the cell's box, with its asymmetric unit a click away, and an mmCIF like a PDB file, its chains as a cartoon. Click an atom for its name and place, and Export saves the view as PNG or the model as GLB, USDZ, STL or OBJ.
Crystallographic Information File
.cif • .mmcif
Format
- MIME type
- chemical/x-cif
- Made by
- The International Union of Crystallography
- Released
- 1991
Inside the file
- Items
- A name and a value, like _cell_length_a
- Loops
- Rows of atoms, bonds and symmetry
- Crystals
- Atoms as fractions of the unit cell
- Markup
- Plain text
Opens in every browser
Filepeek opens CIF and mmCIF files in 3D in Chrome, Edge, Firefox and Safari. On their own, browsers download them or show them as text.
- YouChromeOpens through Filepeek
- YouEdgeOpens through Filepeek
- YouFirefoxOpens through Filepeek
- YouSafariOpens through Filepeek
Apps that open CIF
- WindowsNo app built in opens it • VESTA and Mercury read crystals, UCSF ChimeraX proteins
- MacNo app built in opens it • VESTA and Mercury read crystals, UCSF ChimeraX proteins
- iPhone and iPadNo app built in opens it • Save it here as USDZ to see it in your room
- AndroidNo app built in opens it • Save it here as GLB for 3D apps
Questions
Why does my crystal look like scattered pieces?
A CIF lists only its asymmetric unit, the smallest piece its symmetry repeats. Filepeek places every copy in the cell and keeps each molecule whole, and the Atoms picker shows the asymmetric unit alone.
What's the difference between CIF and mmCIF?
They share their syntax. A small molecule's or a mineral's CIF describes a crystal by its cell and symmetry, while mmCIF, for big molecules, lists every atom of a protein or a nucleic acid. Filepeek tells them apart by what's inside.
Why does my CIF show no atoms?
A structure factor file, like the PDB's 1abc-sf.cif, holds only the measured reflections, and a CIF of a paper's text holds none either. The structure's own CIF has its atoms.
Can I open a CIF from the Cambridge Structural Database?
Yes. A CIF from the CCDC or the Crystallography Open Database opens as its crystal, its unit cell filled, with its name, formula, space group and journal in Show details.
Can I save it for 3D printing?
Yes. Choose Export, then Save as STL or OBJ for the style on show, or GLB for 3D apps and USDZ for an iPhone or iPad.