Per-space-group entry counts within the Crystallography Open Database's inorganic (no-carbon formula) class, by publication year, 1960-2026 (2026 partial through early August). Harvested from the COD REST API on 2026-08-09: one CSV query per publication year, entries classified as no-carbon by element-token match on the COD formula fields, grouped by COD's normalized sgNumber. 226 distinct space groups appear. Companion to the COD composition-flip dataset (019fe3d8-6612-7381-bc5b-2e66e05b836d); no-C totals agree with server-side element-filter counts to <1%. Use cases: symmetry-mix trends, high-throughput fingerprint detection, crystallographic era analysis.
| year | sg_hm | n_entries | sg_number | partial_year | share_of_noc | crystal_system |
|---|---|---|---|---|---|---|
| 1960 | Fm-3m | 28 | 225 | 0.11765 | cubic | |
| 1960 | Pm-3m | 19 | 221 | 0.07983 | cubic | |
| 1960 | P63/mmc | 19 | 194 | 0.07983 | hexagonal | |
| 1960 | P6/mmm | 18 | 191 | 0.07563 | hexagonal | |
| 1960 | Fd-3m | 14 | 227 | 0.05882 | cubic | |
| 1960 | Pnma | 12 | 62 | 0.05042 | orthorhombic | |
| 1960 | P21/c | 11 | 14 | 0.04622 | monoclinic | |
| 1960 | F-43m | 9 | 216 | 0.03782 | cubic | |
| 1960 | null | 9 | 229 | 0.03782 | cubic | |
| 1960 | null | 9 | 164 | 0.03782 | trigonal | |
| 1960 | C2/m | 7 | 12 | 0.02941 | monoclinic | |
| 1960 | P4/mmm | 6 | 123 | 0.02521 | tetragonal |
Where did the structures go?
Capstone of the COD series. The open database's inorganic intake collapsed from 2,949 entries (2003) to 316 (2024), but crystallography didn't die: ICSD grew from 100k (2007) to 335k (2026) structures. Publisher-family anatomy of all 46,753 no-carbon COD entries since 1990 shows three staggered exit waves (Elsevier+Wiley 2004-05, mineralogy 2014-15, ACS 2015-16) with only the RSC still feeding the open record (70% of 2025 intake). Open capture fell from ~15% to ~2% of ICSD's annual intake.
The triclinic surge has three fathers
The COD's triclinic share tripled after 2023, but each year of the surge has a different cause: 2024 is genuine experimental P-1 chemistry made visible by the lowest no-carbon intake since 1961, 2025 is a generative-model batch in disguise, and 2026 is DFT working files deposited as personal communications. None of them are marked as what they are.