NiCl2 x 2 H2O

Ontology mapping

Primary identifier: kgmicrobe.compound:nicl2_x_2_h2o
Ontology term: CHEBI:34887 — nickel dichloride
Ontology label: nickel dichloride

Nutritional roles

Role
TRACE_ELEMENT
Confidence
0.8
Evidence
- Reference type
  COMPUTATIONAL_PREDICTION
  Reference text
  Inferred from curated media-role name pattern
  Curator note
  Provisional role from a curated name-pattern rule; review recommended.

Synonyms (2)

Synonym	Type	Source	Occurrences
NiCl2 x 2H2O	HYDRATE_FORM	kg_microbe
NiCl2·2H2O	HYDRATE_FORM	kg_microbe

Rejected enrichment labels (16)

Provenance-only candidates: these are not synonyms and do not resolve to this record.

Rejected label	Disposition	Source
NiCl2 . 6H2O	REJECTED_LABEL	kg_microbe
NiCl2 x 5 H2O	REJECTED_LABEL	kg_microbe
NiCl2 x 6 H2O	REJECTED_LABEL	kg_microbe
NiCl2 x 6 H2O (0.1% w/v)	REJECTED_LABEL	kg_microbe
NiCl2 x 6H2O	REJECTED_LABEL	kg_microbe
NiCl2 x H2O	REJECTED_LABEL	kg_microbe
NiCl2 · 6H2O	REJECTED_LABEL	kg_microbe
NiCl2.6H2O	REJECTED_LABEL	kg_microbe
NiCl2x6H2O	REJECTED_LABEL	kg_microbe
NiCl2·6H2O	REJECTED_LABEL	kg_microbe
NiCl2⋅6H2O	REJECTED_LABEL	kg_microbe
NiCl2・5H2O	REJECTED_LABEL	kg_microbe
NiCl2・6H2O	REJECTED_LABEL	kg_microbe
NiCl2・H2O	REJECTED_LABEL	kg_microbe
nickel(2+) chloride	REJECTED_LABEL	chebi_synonym_review
nickel(II) chloride	REJECTED_LABEL	chebi_synonym_review

Chemical properties

Data source: CultureBotHT/compounds_to_cas.csv
Retrieval date: 2026-04-09T00:32:50.689620+00:00
Molecular formula: Cl2Ni.2H2O
Inchi: InChI=1S/2ClH.Ni/h2*1H;/q;;+2/p-2
Smiles: [Cl][Ni][Cl]

Evidence (4)

DATABASE_MATCH via CultureMech

[HISTORICAL — superseded by the #321 re-grade below: this record is a hydrate of CHEBI:34887, not an exact match to it] Imported from CultureMech pipeline, quality=DIRECT_MATCH

DATABASE_MATCH via MIM curation (#321/#334)

identifier CHEBI:34887 -> kgmicrobe.compound:nicl2_x_2_h2o; mapping_quality EXACT_MATCH -> NARROW_MATCH. The record is a hydrate of CHEBI:34887 ('nickel dichloride') and was sharing that term's identifier — the identity collapse MAPPING_SEMANTICS §3 forbids, which made a distinct substance indistinguishable from its anhydrous parent downstream. ChEBI has no term for this hydrate and the record carries no verified CAS, so steps 1 and 2 are unavailable and step 3 applies.

DATABASE_MATCH via MIM curation (#321)

molecular_formula 'Cl2Ni' -> 'Cl2Ni.2H2O'. The recorded value described the anhydrous salt while the label names a hydrate, understating the mass by 18 g/mol per water. Corrected because the label states 2 water(s) of hydration, and the recorded formula was byte-identical to the anhydrous parent CHEBI:34887's ChEBI formula ('Cl2Ni') — the mark of a value inherited from the parent rather than measured for this record. Water appended in ChEBI's own dot-separated notation.

DATABASE_MATCH via MIM curation (#342)

mapping_quality NARROW_MATCH -> CLOSE_MATCH, predicate skos:narrowMatch -> skos:closeMatch. narrowMatch asserts this record is *narrower in meaning* than CHEBI:34887 ('nickel dichloride') — a subsumption ChEBI itself denies: it files hydrates under CHEBI:35505 'hydrate', never under the anhydrous compound, which is not an ancestor even transitively. A hydrate is a distinct substance containing the anhydrous form, not a specialization of it. closeMatch claims similarity without subsumption. The ontology_id and the record's own identifier are unchanged.

Occurrence statistics

Total occurrences: 21
Distinct media: 20

Curation history

Timestamp	Curator	Action	New status	Changes
2026-03-09T06:54:18.022301+00:00	import_from_culturemech	IMPORTED	MAPPED	Initial import from CultureMech pipeline
2026-04-09T00:32:50.689620+00:00	enrich_mim_cas_rn_batch	CAS_RN_ADDED	MAPPED	Added CAS-RN 7791-20-0 from CultureBotHT/compounds_to_cas.csv
2026-04-18T00:00:00+00:00	cbclaw_kg_microbe_sweep LLM	ADDED_SYNONYMS	MAPPED	Added 16 synonyms from kg-microbe P4.4 enrichment: NiCl2 . 6H2O, NiCl2 x 2H2O, NiCl2 x 5 H2O, NiCl2 x 6 H2O, NiCl2 x 6 H2O (0.1% w/v), ... (11 more)
2026-05-01T07:35:35.526999+00:00	auto_classify_ingredient_type	AUTO_CLASSIFY_INGREDIENT_TYPE		set ingredient_type=SINGLE_INGREDIENT (CHEBI primary)
2026-05-01T08:08:31.624332+00:00	auto_classify_ingredient_type	AUTO_BACKFILL_CHEBI_CHEMISTRY		molecular_formula=Cl2Ni; inchi=InChI=1S/2ClH.Ni/h2*1H;/q;;+2/p-2; smiles=[Cl][Ni][Cl]
2026-05-02T03:12:17.403330+00:00	auto_classify_ingredient_type	AUTO_CLASSIFY_INGREDIENT_TYPE		set ingredient_type=SINGLE_INGREDIENT (chemical structure populated (molecular_formula))
2026-06-02T07:05:13.392044+00:00	infer_roles_from_name_lists	ANNOTATED		Added media role: MINERAL (confidence: 0.80)
2026-06-09T05:23:46.812639+00:00	correct_stale_ontology_labels.py	CORRECTED		ontology_label 'NiCl2 x 2 H2O' -> 'nickel dichloride': synced to canonical CHEBI label (preferred_term 'NiCl2 x 2 H2O' unchanged).
2026-07-20T00:00:00+00:00	migrate_media_roles_to_facets	ANNOTATED		Migrated legacy media_roles to role facets (#128): MINERAL -> nutritional_roles.TRACE_ELEMENT
2026-08-13T00:00:00+00:00	mint_hydrate_registry_terms	MINTED_REGISTRY_FOR_HYDRATE		identifier CHEBI:34887 -> kgmicrobe.compound:nicl2_x_2_h2o; mapping_quality EXACT_MATCH -> NARROW_MATCH (#321/#334); §3 step 3.
2026-08-13T00:00:00+00:00	add_water_of_hydration	ADDED_WATER_OF_HYDRATION		molecular_formula 'Cl2Ni' -> 'Cl2Ni.2H2O' (#321); the label states 2 water(s) of hydration, and the recorded formula was byte-identical to the anhydrous parent CHEBI:34887's ChEBI formula ('Cl2Ni') — the mark of a value inherited from the parent rather than measured for this record. Water appended in ChEBI's own dot-separated notation.
2026-08-13T00:00:00+00:00	fix_scrambled_hydrate_cas	WITHDREW_WRONG_CAS		cas_rn '7791-20-0' removed (#320/#334). It denotes nickel chloride hexahydrate, which contradicts the hydration state this record's label states — the #334 scrambling, where one CAS is applied across a salt family regardless of hydration. No verified replacement is available: the record's term CHEBI:34887 is anhydrous nickel dichloride, so its xref 7718-54-9 is the anhydrous CAS — wrong for a dihydrate. Cleared rather than substituted, because swapping in a second wrong number would read as a correction while still publishing a false identifier.
2026-08-13T00:00:00+00:00	regrade_hydrate_to_close_match	REGRADED_HYDRATE_TO_CLOSE_MATCH		mapping_quality NARROW_MATCH -> CLOSE_MATCH (#342); a hydrate is not subsumed by its anhydrous form, and ChEBI does not model it as such.
2026-08-27T03:16:39.519619+00:00	refresh_occurrence_statistics	CORRECTED		occurrence_statistics 13/13 -> 20/21 (media_count/total_occurrences), derived from distinct CultureMech recipe ids in the #337 occurrence table. The prior values came from the importer retired in #453, whose media_count counted a list truncated to 50 examples (#449). [source=ingredient_occurrences.tsv culturemech_rev=15a4da5c08 rows=194137 distinct_recipes=15257]
2026-09-12T00:00:00+00:00	fix_malformed_hydrate_identities	REJECTED_MALFORMED_HYDRATE_ALIASES	MAPPED	Marked malformed hydrate alias(es) as REJECTED_LABEL so they remain on their own #344 local identities only: 'NiCl2 x 5 H2O', 'NiCl2・5H2O'.
2026-09-12T00:00:00+00:00	reject_hidden_hydrate_synonym_collapses	REJECTED_HIDDEN_HYDRATE_SYNONYMS	MAPPED	Marked hidden hydrate synonym(s) as REJECTED_LABEL so this record no longer resolves sibling hydrate identities (#251): 'NiCl2 . 6H2O', 'NiCl2 x 6 H2O', 'NiCl2 x 6 H2O (0.1% w/v)', 'NiCl2 x 6H2O', 'NiCl2 x H2O', 'NiCl2 · 6H2O', 'NiCl2.6H2O', 'NiCl2x6H2O', 'NiCl2·6H2O', 'NiCl2⋅6H2O', 'NiCl2・6H2O', 'NiCl2・H2O'.
2026-09-22T20:41:14.285965+00:00	claude LLM	REJECTED_PARENT_NAME_SYNONYMS		Retyped names of the parent compound or of a different hydrate as provenance-only REJECTED_LABEL, because this record is a distinct salt, hydrate or tombstone form and the label index resolved the parent's name here (#232): 'nickel(2+) chloride'; 'nickel(II) chloride'. Preserved original text and source metadata. No identity, mapping, role, or remaining-synonym claim was adjudicated.
2026-10-12T03:21:01.652049+00:00	claude LLM	REMOVED_PARENT_IDENTITY	MAPPED	Removed kg_microbe_node_id CHEBI:34887, the anhydrous nickel dichloride identity. The record keeps its distinct dihydrate identifier kgmicrobe.compound:nicl2_x_2_h2o, minted under §3 step 3 (#321/#334) because ChEBI has no term for this hydration state, and only a CLOSE_MATCH parent annotation (#342). The stale KG node field contradicted that ruling and kept the unified mapping publishing the anhydrous parent as the identity (#808, culturebotai-claw#571). No replacement KG node is asserted.