Analyse a .SD file

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What is a .SD file?

SD is the same format as SDF - a stack of Molfiles, each followed by tagged data fields and terminated by a line of four dollar signs.

Did you know
  • The four-dollar-sign separator is what lets a single file hold a whole chemical library and still be read a molecule at a time.
  • Analyser handles .SD alongside related formats such as .MOL, .SDF, .MOL2 and more.
  • In Analyser's format library, .SD sits in the System & disk category.
What Analyser reads
Open chemical structures and see the molecule: MOL and SDF connection tables, MOL2, plain XYZ coordinates, Protein Data Bank entries and mmCIF/CIF crystallographic files, all drawn in an interactive 3D viewer you can rotate, zoom and restyle. Small molecules come up as ball-and-stick with the standard element colours; proteins and nucleic acids get a cartoon instead, drawing each chain as a ribbon along its backbone with helices and sheets picked out and any bound ligand still shown as sticks - which is the only way a structure of tens of thousands of atoms is readable at all. Alongside the picture, the composition is worked out from the atoms actually present rather than from any label in the file: molecular formula in Hill notation, molecular weight, net charge, element counts, and for a macromolecule the chain, residue and secondary-structure counts plus every non-polymer group - bound drugs, cofactors, metal ions and crystallisation buffer. PDB headers give up the entry ID, title, experimental method and resolution; an SDF is stepped through record by record with each molecule's tagged data fields read out.
Depth of analysis
.SD is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
Open a .SD file
Drag a .SD file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.
Related formats
.MOL · .SDF · .MOL2 · .XYZ · .PDB · .ENT · .PQR · .GRO · .CIF · .MMCIF · .MCIF. See all supported file types.