List of Chromium Compounds

From plating shops to academic labs, chromium shows up in many guises — as pigments, catalysts, corrosion inhibitors, and analytical reagents. Knowing which compound does what helps when choosing materials, assessing risks, or interpreting experimental results.

There are 35 Chromium Compounds, ranging from Ammonium dichromate to Zinc chromate. For each entry you’ll find below the Formula, Oxidation state, Main uses / notable properties so you can quickly compare structure, typical applications, and hazards before digging deeper.

How do oxidation states change the behavior of chromium compounds?

Oxidation state largely governs color, reactivity, and toxicity: Cr(III) species are generally more stable and less toxic (used in dyes, tanning, catalysts), whereas Cr(VI) compounds are strong oxidizers, highly soluble, and much more hazardous (used historically in plating and pigments), so identification of the oxidation state is key for handling and disposal.

Which chromium compounds should I treat as hazardous in a lab or workplace?

Treat all Cr(VI) compounds as hazardous — they’re carcinogenic and require engineering controls, PPE, and regulated waste procedures; many Cr(III) salts are lower risk but still benefit from standard chemical hygiene and proper storage, so consult safety data sheets for the specific compound you’ll find below.

Chromium Compounds

Images and Descriptions

Chromium(III) oxide

Hard green powder used as pigment and refractory material; chemically stable and corrosion-resistant. Found in ceramics, coatings and as a passivating layer on stainless alloys. Low solubility; not highly toxic but inhalation of dust can irritate lungs.

Chromium(VI) oxide

Red crystalline solid and source of chromic acid; powerful oxidizer used in metal finishing and organic oxidation. Highly corrosive and a known human carcinogen; causes severe burns and respiratory harm, environmental contaminant requiring strict handling and disposal.

Chromium(II) oxide

Black crystalline powder used as reducing agent and intermediate in inorganic synthesis; sensitive to air and moisture, readily oxidizes to Cr(III) species. Toxic by inhalation and must be handled under inert atmosphere in specialized labs.

Chromium(IV) oxide

Dark metallic-black crystalline solid used historically as magnetic pigment in audio tapes and data storage. Ferromagnetic at room temperature with high coercivity. Fine dust is hazardous and inhalation or environmental release poses health and contamination risks.

Chromium(II) chloride

Blue-green salt used in organic and inorganic synthesis as a one-electron reducing agent and source of Cr(II). Hygroscopic and air-sensitive; oxidizes easily to Cr(III). Toxic if ingested and can produce harmful dust or vapors.

Chromium(III) chloride

Purple or green crystalline solid (hydrated forms common) used as a catalyst precursor and laboratory reagent. Moderately soluble in water; essential nutrient in trace amounts as Cr(III), but soluble salts can irritate skin and eyes.

Chromium(III) sulfate

Violet or green solid used historically in leather tanning and as a mordant for dyes; also a precursor in some plating baths. Soluble hydrated forms release Cr(III); less toxic than Cr(VI) but still requires safe handling to avoid exposure.

Chromium(II) sulfate

Blue-green crystalline salt used as a reducing reagent in laboratory syntheses and studies of Cr(II) chemistry. Air- and moisture-sensitive; oxidizes to Cr(III) rapidly. Corrosive to tissues; handle under inert conditions to limit exposure.

Chromic acid

Yellow-orange aqueous solution of chromium(VI), produced from CrO3. Powerful oxidizer used for cleaning glass and metal etching. Highly corrosive and carcinogenic; causes severe burns and environmental harm, requiring strict waste controls.

Potassium dichromate

Orange crystalline oxidizing salt widely used in laboratories for titrations and as a standard oxidant; former industrial use in tanning and cleaning. Strong carcinogen and corrosive; disposal and handling strictly regulated due to environmental toxicity.

Potassium chromate

Yellow ionic solid used as a laboratory indicator, corrosion tester, and intermediate in producing dichromates. Soluble and strongly alkaline in solution. Contains carcinogenic Cr(VI); toxic by ingestion and environmentally persistent.

Sodium dichromate

Orange crystalline salt used industrially to produce chromate and dichromate chemicals and as an oxidizer. Strongly oxidizing and carcinogenic; highly regulated for worker safety and environmental releases, persistent in aquatic systems.

Sodium chromate

Yellow water-soluble salt used as an intermediate for chromium chemical manufacture, tanning and corrosion inhibitors. Alkaline and contains Cr(VI); acutely toxic and carcinogenic, requiring controlled handling and disposal to protect health and ecosystems.

Ammonium dichromate

Orange crystalline oxidizer historically used in demonstrations that produce large exothermic decompositions. Used in some matches and pyrotechnics. Highly toxic, carcinogenic and an environmental hazard; spontaneous decomposition risk and strict regulatory controls apply.

Chromyl chloride

Red volatile liquid used as an oxidizing reagent and in the classic qualitative test for chlorides (chromyl chloride test). Extremely corrosive, volatile and carcinogenic; inhalation and skin contact are dangerous and it reacts violently with water.

Chromium hexacarbonyl

Colorless volatile organometallic solid used as a precursor in surface science and CVD studies. Cr(0) carbonyl; toxic, volatile and flammable. Inhalation or skin exposure risks; decomposes to toxic CO under heating.

Chromocene

Orange or red paramagnetic sandwich complex (bis(cyclopentadienyl)chromium) used in organometallic studies. Air-sensitive and oxidizes readily. Can be pyrophoric; toxic by inhalation or ingestion and requires glovebox techniques for safe handling.

Bis(benzene)chromium

Air-sensitive orange crystalline sandwich complex where chromium is bonded to two benzene rings. Studied for bonding and electronic properties. Volatile and toxic; must be handled under inert gas and away from heat or open flames.

Chromium(III) acetylacetonate

Green crystalline complex used as a stable model compound in coordination chemistry and occasionally as a catalyst. Moderately air-stable but soluble in organic solvents. Low acute toxicity compared with Cr(VI) but standard lab precautions required.

Chromium(III) nitrate

Purple crystalline salt used as a source of Cr(III) in catalyst preparation and materials chemistry. Hygroscopic and oxidizing in concentrated form; ingestion or inhalation can irritate mucous membranes and requires safe laboratory handling.

Chromium(III) acetate

Deep green crystalline complex salt used in research and occasionally as a catalyst. Soluble in water and organic solvents depending on hydration. Low solubility limits absorption; handle with standard laboratory PPE to avoid skin and respiratory exposure.

Chromium(III) fluoride

Green crystalline solid used as a precursor in ceramics and specialty materials. Insoluble in water but reacts with acids. Contains Cr(III) which is less toxic than Cr(VI), but inhalation or prolonged exposure can still cause harm.

Chromium(II) fluoride

Blue crystalline solid used in specialized inorganic syntheses and as a reducing agent. Sensitive to air and moisture and oxidizes to Cr(III). Toxic if inhaled or ingested; laboratory precautions required.

Chromium(III) bromide

Dark red crystalline solid studied for its layered magnetic properties and as a precursor to two-dimensional materials research. Hygroscopic and air-sensitive; handle carefully to avoid inhalation and skin contact exposure.

Chromium(II) bromide

Gray to green crystalline salt used as a source of Cr(II) in organic and inorganic reductions. Air-sensitive and decomposes on exposure; toxic by ingestion or inhalation and requires inert-atmosphere techniques.

Chromium(III) iodide

Black to dark brown layered crystals recently studied as an atomically thin ferromagnet. Sensitive to air and moisture, degrading on exposure. Novel for spintronics research; handle inside inert gloveboxes to avoid health hazards and material degradation.

Chromium(II) iodide

Dark crystalline solid used in specialized syntheses as a Cr(II) source and reductant. Highly air-sensitive and reacts violently with moisture. Toxic and corrosive; requires inert atmosphere and protective handling to avoid exposure.

Chromium(III) hydroxide

Green gelatinous precipitate formed when Cr(III) salts hydrolyze; used or encountered in water-treatment chemistry. Sparingly soluble and relatively low toxicity compared with Cr(VI) but can still irritate skin and respiratory tract upon exposure.

Lead chromate

Bright yellow insoluble pigment historically used in paints as ‘chrome yellow’. Provides durable, lightfast color but contains both lead and carcinogenic Cr(VI). Highly toxic and environmentally persistent; largely phased out for safety.

Strontium chromate

Yellow crystalline chromate pigment used in anti-corrosion primers for metals. Provides long-lasting protection but contains Cr(VI) and poses significant health and environmental hazards; subject to strict regulations and replacement by safer alternatives.

Zinc chromate

Yellow insoluble chromate used as corrosion-inhibiting pigment in primers and coatings. Effective but contains toxic, carcinogenic Cr(VI) and persists in the environment; use now restricted and often replaced by safer inhibitors.

Barium chromate

Yellow insoluble chromate salt used historically as pigment and corrosion inhibitor. Like other Cr(VI) chromates it’s carcinogenic and environmentally harmful; care needed during manufacture, use, and disposal to prevent soil and water contamination.

Chromium(III) oxalate

Green crystalline coordination compound of oxalate ligands used in materials synthesis and coordination studies. Moderately air-stable; oxalate decomposition can release CO2. Less hazardous than Cr(VI), but ingestion or dust inhalation poses health risks.

Chromium(III) perchlorate

Red or violet crystalline salt used in specialized research as a source of Cr(III) and as oxidizing perchlorate counterion. Strong oxidizer; perchlorate presence adds flammability and handling hazards. Toxic if ingested or inhaled.

Chromium(III) carbonate

Greenish poorly soluble carbonate of Cr(III) occurring in some syntheses and as a lab curiosity. Decomposes on heating to oxides and CO2. Lower toxicity than Cr(VI) but dust and ingestion remain hazardous.

Compounds of Other Elements