{
  "search_queries": [
    "crystallography.net/cod result.php text=periclase",
    "crystallography.net/cod result.php el1=Cs el2=Cl",
    "crystallography.net/cod result.php text=gallium arsenide (held: no clean 1:1 GaAs zinc-blende entry located)",
    "crystallography.net/cod result.php el1=Cu nel=1 (held: element-only query too broad/slow to isolate a clean elemental-copper entry in-session)"
  ],
  "selection_unit": "Official COD crystal structures plus assistant-authored method notes",
  "resources": [
    {
      "id": "1000053",
      "url": "https://www.crystallography.net/cod/1000053.html",
      "decision": "selected",
      "route": "raw_structure_or_simulation",
      "materials": [
        "complete CIF",
        "information card"
      ],
      "license": "CC0 per COD policy; original Sasaki/Fujino/Takeuchi 1979 (Proc. Japan Acad. Ser. B 55(2):43-48, doi:10.2183/pjab.55.43) attribution retained"
    },
    {
      "id": "9008789",
      "url": "https://www.crystallography.net/cod/9008789.html",
      "decision": "selected",
      "route": "raw_structure_or_simulation",
      "materials": [
        "complete CIF",
        "information card"
      ],
      "license": "CC0 per COD policy; original Wyckoff Crystal Structures 1963 attribution retained (same source volume already used for halite in materials-cell-v04-001)"
    },
    {
      "id": "gaas-search",
      "url": "https://www.crystallography.net/cod/result.php?el1=Ga&el2=As&format=json",
      "decision": "hold",
      "acquisition": "117 Ga/As-containing entries reviewed; no clean 1:1 zinc-blende GaAs entry (formula Ga1As1, 8 atoms/cell) found among them within this session. Not substituted with an unverified or mismatched structure.",
      "reason": "Session time budget; a dedicated retrieval pass could search AMCSD or a materials database directly for a semiconductor zinc-blende GaAs deposit in a future batch."
    },
    {
      "id": "cu-search",
      "url": "https://www.crystallography.net/cod/result.php?el1=Cu&nel=1&format=json",
      "decision": "hold",
      "acquisition": "Query returned the full single-element COD subset (over 10 MB, request timed out before completion); no elemental-copper entry was isolated and verified in-session.",
      "reason": "Would need a narrower, ID-targeted lookup rather than a broad element filter; deferred to a future batch."
    }
  ],
  "downloads": [
    {
      "file": "1000053.cif",
      "url": "https://www.crystallography.net/cod/1000053.cif",
      "bytes": 4997
    },
    {
      "file": "1000053-card.html",
      "url": "https://www.crystallography.net/cod/1000053.html",
      "bytes": 7540
    },
    {
      "file": "9008789.cif",
      "url": "https://www.crystallography.net/cod/9008789.cif",
      "bytes": 2529
    },
    {
      "file": "9008789-card.html",
      "url": "https://www.crystallography.net/cod/9008789.html",
      "bytes": 13144
    },
    {
      "file": "structure-factor",
      "url": "https://www.iucr.org/what-we-do/education/pamphlets/introduction-calculation-of-structure-factors",
      "error": "HTTP Error 403: Forbidden"
    },
    {
      "file": "bragg",
      "url": "https://dictionary.iucr.org/Bragg%27s_law",
      "error": "HTTP Error 403: Forbidden"
    }
  ],
  "acquired_date": "2026-09-21"
}