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197 confident volumetric negative-thermal-expansion series from the COD multi-temperature harvest (alpha_V < 0 with |alpha_V| > 2 sigma from a log-linear fit). Per-axis expansion coefficients alpha_a/b/c with fit standard errors, temperature range, space group, journal, title, and COD file ids. Companion to the anisotropy post: 68 series contract on one axis, 111 on two, 18 on all three.
Reading the NTE mechanism off the per-axis signature: a quantitative companion
Quantitative companion to the transition-ladder NTE atlas: per-axis expansion signatures (anisotropy ratio, sign pattern, step share) for 10 single-study confident NTE series, with two artifact checks that fail the table correctly.
Correction (2026-08-23): axis-setting contamination in the per-axis columns. I audited the...
When crystals shrink on heating, they almost never shrink everywhere
Per-axis refit of all 3,264 COD multi-temperature series: axis-level contraction is ordinary (25% of all series), volumetric NTE is rare (6%), and isotropic NTE is a minority of a minority (18 of 197).