# Potassium trihydrogen dioxalate dihydrate

**CAS:** 6100-20-5  
**PubChem CID:** [23664780](https://pubchem.ncbi.nlm.nih.gov/compound/23664780)  
**Molecular formula:** C₈H₄K₈O₁₈  
**Molar mass:** 254.19 g/mol  
**IUPAC:** potassium;2-hydroxy-2-oxoacetate;oxalic acid;dihydrate  
**SMILES:** `C(=O)(C(=O)O)O.C(=O)(C(=O)[O-])O.O.O.[K+]`  
**InChIKey:** `KPFHSTZUXXJAES-UHFFFAOYSA-M`  
**InChI:** `InChI=1S/2C2H2O4.K.2H2O/c2*3-1(4)2(5)6;;;/h2*(H,3,4)(H,5,6);;2*1H2/q;;+1;;/p-1`  

## Physicochemical properties

| Parameter | Value |
|---|---|
| PSA | 154 Ų |
| Hydrogen bond donors | 5 |
| Hydrogen bond acceptors | 10 |
| Rotatable bonds | 2 |
| Heavy atoms | 15 |

## 3D structure

The molecule contains 22 atoms connected by 18 chemical bonds. Interactive 3D model available at: https://molgod.org/molecule/6100-20-5/

## GHS classification

**Signal word:** Danger

**Pictograms:** GHS05, GHS07, GHS08

### Hazard statements (H)

- **H302** — Harmful if swallowed
- **H312** — Harmful in contact with skin
- **H315** — Causes skin irritation
- **H318** — Causes serious eye damage
- **H335** — May cause respiratory irritation
- **H373** — May cause damage to organs through prolonged or repeated exposure

### Precautionary statements (P)

- **P260** — Do not breathe dust/fume/gas/mist/vapours/spray

## Synonyms

- 6100-20-5
- Potassium trihydrogen dioxalate dihydrate
- POTASSIUM TETROXALATE DIHYDRATE
- Potassium tetroxalate dihydrate [MI]
- OQ8R5Z714T
- Potassium oxalate (KH3(C2O4)2) dihydrate
- Ethanedioic acid, potassium salt, hydrate (2:1:2)
- RefChem:868175
- 612-064-2
- Potassium tetraoxalate dihydrate

## Regulatory compliance checklist

Status based on: ADR 2025 (Table A), REACH Annex XVII, CLP Annex VI (harmonised classification), hazard class from the m14-spill DB, SVHC, GIS and the Polish OEL list. Principle: no data = no claim (we do NOT declare "no restrictions" without a basis).

4 required / 12 items

### SDS (Safety Data Sheet) available

- **required** (required / sds)
- How to comply: Requirement: current SDS compliant with Reg. 1907/2006 (REACH) Annex II, 16-section format.
- [Source / form](https://echa.europa.eu/information-on-chemicals)

### Compliant CLP label (pictograms + signal word + H/P)

- **required** (required / clp_label)
- How to comply: The label must include: GHS pictograms, the signal word (Danger/Warning), hazard (H) and precautionary (P) statements, and manufacturer details. Required since 2010 (substances) and 2015 (mixtures).
- [Source / form](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008R1272)

### Chemical OSH training (substance-specific)

- **required** (required / bhp_training)
- How to comply: Laboratory staff: initial training (general induction + job-specific) + refresher training every 5 years (or every 3 for engineering/technical positions). Documentation kept in personnel files.
- [Source / form](https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20040180169)

### BDO registration (Polish Waste Database)

- **not applicable** (not_applicable / bdo_registration)
- How to comply: The verified GHS classification does not indicate classes resulting in hazardous waste — BDO registration for this substance is not required. Verify the EWC code for the specific waste form.
- [Source / form](https://bdo.mos.gov.pl/)

### ADR transport (international agreement)

- **to be verified** (unknown / adr_transport)
- How to comply: No ADR data in the MOL-GOD dataset for this CAS number. Do NOT assume there are no restrictions — before shipping, verify the transport classification in ADR 2025 (Table A) and in section 14 of the safety data sheet (SDS).
- [Source / form](https://unece.org/transport/dangerous-goods/adr-2025-files)

### REACH registration (>1 t/year EU import)

- **conditional** (conditional / reach_registration)
- How to comply: Importers/manufacturers ≥1 tonne/year must register the substance with ECHA (technical dossier + Chemical Safety Report if ≥10 t). Check the ECHA Annex VI / registered substances list.
- [Source / form](https://echa.europa.eu/regulations/reach/registration)

### SVHC notification (Substances of Very High Concern)

- **to be verified** (unknown / svhc_declaration)
- How to comply: SVHC status not verified against the available dataset — check the current ECHA candidate list; do not assume the absence of an entry.
- [Source / form](https://echa.europa.eu/candidate-list-table)

### REACH Annex XIV (authorisation list)

- **to be verified** (unknown / reach_annex_xiv)
- How to comply: Not verified against the ECHA Authorisation List — check REACH Annex XIV.
- [Source / form](https://echa.europa.eu/authorisation-list)

### REACH Annex XVII (use/marketing restrictions)

- **to be verified** (unknown / reach_annex_xvii)
- How to comply: No entry in the harmonised classification dataset (CLP Annex VI) for this CAS number — status of entries 28–30 (CMR ban) NOT VERIFIED; do not assume the restriction does not apply. The dataset of Annex XVII restrictions is also incomplete — check the consolidated Annex XVII and the harmonised CMR classification on the ECHA website.
- [Source / form](https://echa.europa.eu/substances-restricted-under-reach)

### OEL — Occupational Exposure Limit in the working environment

- **to be verified** (unknown / nds_workplace)
- How to comply: No NDS data in the MOL-GOD dataset (incomplete set — ~41 of ~600 substances in the list). Absence does NOT mean there is no NDS — check the full list in Dz.U. 2024 poz. 1017 (Regulation of the Ministry of Family and Social Policy of 4 September 2024), and where none exists apply the OEL from EU directives or values recommended by NIOSH/ACGIH.
- [Source / form](https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20240001017)

### GIS register (precursors / psychotropics)

- **to be verified** (unknown / gis_register)
- How to comply: Does not appear in the available working set of precursors (list incomplete). Absence is NOT a confirmation — verify against Annex I of Reg. (EC) 273/2004 and the GIS list before placing on the market.
- [Source / form](https://www.gov.pl/web/gis)

### Safety Data Sheet in Polish

- **required** (required / sds_pl)
- How to comply: Requirement: SDS in Polish for trade in PL (Art. 31 REACH + Chemical Substances Act Art. 17).
- [Source / form](https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20012112135)


## Data sources

- [PubChem CID 23664780](https://pubchem.ncbi.nlm.nih.gov/compound/23664780)
- [NIST WebBook](https://webbook.nist.gov/cgi/cbook.cgi?ID=6100-20-5)
- [ChEMBL](https://www.ebi.ac.uk/chembl/g/#search_results/all/query=6100-20-5)

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*Last updated: 2026-10-17 · Generator: MOL-GOD v3.12.33*