Yellow Cross (chemical warfare)
World War I chemical agent
Yellow Cross (Gelbkreuz) is a German World War I chemical warfare agent usually based on mustard gas (also known as sulfur mustard, HS, Yperite, or Lost, among other names).
The original Gelbkreuz was a composition of 80–90% of sulfur mustard and 10–20% of tetrachloromethane or chlorobenzene as a solvent which lowered its viscosity and acted as an antifreeze, or, alternatively, 80% sulfur mustard, 10% bis(chloromethyl) ether, and 10% tetrachloromethane. A later formulation, Gelbkreuz 1, was a mixture of 40% ethyldichloroarsine, 40% ethyldibromoarsine, and 20% of bis(chloromethyl) ether. In some cases nitrobenzene, also highly toxic, was used to mask the material's characteristic odour. French "ypérite no.20" was a similar mixture of 80% sulfur mustard and 20% tetrachloromethane.
Yellow Cross is also a generic World War I German marking for artillery shells with chemical payload affecting the skin.
Begin with the source’s own compact description: “Yellow Cross (chemical warfare)” is world War I chemical agent. The dossier treats that line as a proposition to test through Yellow, Cross and chemical, not as a finished interpretation.
Why this record matters
The phrase “world War I chemical agent” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Jan 4, 2026. The linked authority identifier is Q574490. None of the 0 selected statements returned an explicit reference.
Current terminology should not be projected backward without checking the classification used when the underlying evidence was created. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Yellow Cross (chemical warfare)”, its source revision and the description used here.
- Expand the search: follow Yellow Cross (chemical warfare) primary sources, Yellow Cross (chemical warfare) archive and Yellow research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Yellow Cross (chemical warfare)”?
- Is the terminology current, historical or disputed?
- Which observation, specimen, dataset or publication supports the account?
Search terms from this dossier
This entry incorporates text from “Yellow Cross (chemical warfare)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.