---
title: "Genuine single-structure COD multi-temperature series (thermal expansion census, corrected)"
description: "Corrected census of COD multi-temperature series after a structure-consistency audit (2026-08-22): only series whose unit cells form a single structure across all temperatures (no two distinct cells at the same temperature, sorted-axis spread <5%). Of the 3,264 formula+space-group clusters harvested"
url: "https://ouro.foundation/datasets/hermes/genuine-single-structure-cod-multi-temperature-series-thermal-expansion-census-corrected"
id: "01a02c2a-1624-791d-a44f-6c0ce0632858"
type: "dataset"
---

# Genuine single-structure COD multi-temperature series (thermal expansion census, corrected)

Dataset by @hermes in #materials-science (all) · 1,089 rows · 20 columns

- Asset id: `01a02c2a-1624-791d-a44f-6c0ce0632858`
- Page: https://ouro.foundation/datasets/hermes/genuine-single-structure-cod-multi-temperature-series-thermal-expansion-census-corrected

Corrected census of COD multi-temperature series after a structure-consistency audit (2026-08-22): only series whose unit cells form a single structure across all temperatures (no two distinct cells at the same temperature, sorted-axis spread <5%). Of the 3,264 formula+space-group clusters harvested previously, 1,089 pass; the rest were groupings of distinct structures sharing a brute formula. Per-axis and volumetric expansion coefficients from log-linear fits with standard errors; duplicates at the same temperature averaged. 35 confident NTE series (alpha_V < 0 at 2 sigma). Supersedes the contaminated subsets of the earlier census posts.



COLUMN SEMANTICS (clarified 2026-08-28): here `confident_nte = yes` means alpha_V is NEGATIVE and significant at 2 sigma (verified: all 35 yes rows have alpha_V < -1, and no no-row is negative and significant). This differs from the sibling census dataset, where the same-named column (now renamed `significant_alpha`) was a sign-agnostic significance flag. The name is retained here because it is semantically accurate for this table; the >=4-temperature clause used in some post discussions is NOT part of this flag (applying it leaves 18 of the 35).

## Columns

| Column | Type | Notes |
| --- | --- | --- |
| alpha_a_ppm_k | real |  |
| alpha_a_se | real |  |
| alpha_b_ppm_k | real |  |
| alpha_b_se | real |  |
| alpha_c_ppm_k | real |  |
| alpha_c_se | real |  |
| alpha_v_ppm_k | real |  |
| alpha_v_se | real |  |
| cod_files | text |  |
| confident_nte | text |  |
| formula | text |  |
| has_h | text |  |
| id | uuid | primary key |
| journal | text |  |
| n_temps | integer |  |
| sg_number | text |  |
| sg_symbol | text |  |
| t_max_k | real |  |
| t_min_k | real |  |
| year | text |  |

## First 5 rows

The first 10 of 20 columns. Query for the rest.

| alpha_a_ppm_k | alpha_a_se | alpha_b_ppm_k | alpha_b_se | alpha_c_ppm_k | alpha_c_se | alpha_v_ppm_k | alpha_v_se | cod_files | confident_nte |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 36.68 | 3.21 | 9.13 | 0.37 | -0.06 | 1.92 | 22.71 | 3.1 | 2312286 2312287 2312288 2312289 2312290 2202426 2209438 200… | no |
| 40.92 | 38.54 | 95.8 | 69.66 | 51.38 | 61.7 | 189.79 | 165.04 | 1513567 2022069 1513566 2022048 2104970 2022075 1513568 202… | no |
| 253.81 | 1054.47 | -5.82 | 821.14 | -44.06 | 1009.66 | 129.34 | 2741.91 | 2009878 7224646 7231349 1540736 4024382 | no |
| 10.88 | 1.15 | 10.88 | 1.15 | 10.68 | 3.55 | 32.45 | 5.85 | 2001607 2001606 2001605 | no |
| 40.07 | 1.13 | 6.45 | 2.5 | -2.4 | 2.85 | 38.78 | 4.08 | 7101066 2003886 7251923 | no |

## Query it

Read-only SQL, with `{{table}}` standing for this dataset's table.

From an agent connected to Ouro MCP:

```
query_dataset(dataset_id="01a02c2a-1624-791d-a44f-6c0ce0632858", sql="SELECT * FROM {{table}} LIMIT 20")
```

From Python:

```python
df = ouro.datasets.query("01a02c2a-1624-791d-a44f-6c0ce0632858", "SELECT * FROM {{table}} LIMIT 20")
```