Cobalt(II) hydroxide

Synonym(s):Cobalt dihydroxide;Cobalt⁽²⁺⁾ hydroxide;Cobaltous hydroxide

CAS NO.：21041-93-0
Empirical Formula: CoH2O2
Molecular Weight: 92.95
MDL number: MFCD00016015
EINECS: 244-166-4
SAFETY DATA SHEET (SDS)
Update Date: 2024-12-18 13:37:16

What is Cobalt(II) hydroxide?

Description

The addition of alkali metal hydroxides to solutions of cobalt(II) salts results in the precipitation of cobalt(II) hydroxide in either a blue or pink form depending upon the conditions. The pink form is the more stable of the two and is obtained when a suspension of the blue form is allowed to stand or is warmed. Cobalt(II) hydroxide is amphoteric, dissolving in alkalis to form blue solutions of the [Co(OH)4]2- ions. In the presence of alkali, suspensions of Co(OH) are oxidized by air to the brown CoO(OH), this oxidation being brought about rapidly by oxidants such as hypochlorite, bromine water or hydrogen peroxide. The pink Co(OH)2 (density 3.597) has the brucite (Mg(OH)2) structure in which the cobalt atoms are surrounded by six hydroxides. The blue form is more disordered, but its structure is not known for certain.

Chemical properties

Rose-red powder.Soluble in acids and ammonium salt solutions; insoluble in water and alkalies.

The Uses of Cobalt(II) hydroxide

Cobalt(II) hydroxide is used as a drying agent for paints and varnishes. It acts as an aid to dry the lithographic inks and catalyst in the preparation of battery electrode impregnating solutions. It is also involved in the synthesis of other cobalt compounds.

The Uses of Cobalt(II) hydroxide

Cobalt salts, paint and varnish driers, catalyst, storage-battery electrodes.

What are the applications of Application

Cobalt(II) hydroxide is a drying agent, catalyst, and precursor to other cobalt compounds

Flammability and Explosibility

Not classified

Properties of Cobalt(II) hydroxide

Melting point:	°Cd ec.)
Density	3.597 g/mL at 25 °C(lit.)
vapor pressure	0Pa at 20℃
storage temp.	Inert atmosphere,Room Temperature
solubility	slightly soluble in H2O; soluble in acid solutions
form	Powder
color	Pink to purple
Specific Gravity	3.597
PH	9.15(1 mM solution);9.15(10 mM solution);9.15(100 mM solution)
Water Solubility	Soluble in acids and ammonia. Very slightly soluble in water. Insoluble in dilute alkalis.
Sensitive	Air Sensitive
Merck	14,2442
Solubility Product Constant (Ksp)	pKsp: 14.23
Exposure limits	ACGIH: TWA 0.02 mg/m3
Stability:	Stability
CAS DataBase Reference	21041-93-0(CAS DataBase Reference)
EPA Substance Registry System	Cobalt hydroxide (Co(OH)2) (21041-93-0)

Safety information for Cobalt(II) hydroxide

Signal word	Danger
Pictogram(s)	Skull and Crossbones Acute Toxicity GHS06 Health Hazard GHS08 Environment GHS09
GHS Hazard Statements	H302:Acute toxicity,oral H317:Sensitisation, Skin H319:Serious eye damage/eye irritation H330:Acute toxicity,inhalation H334:Sensitisation, respiratory H350:Carcinogenicity H360:Reproductive toxicity H410:Hazardous to the aquatic environment, long-term hazard
Precautionary Statement Codes	P273:Avoid release to the environment. P280:Wear protective gloves/protective clothing/eye protection/face protection. P301+P312:IF SWALLOWED: call a POISON CENTER or doctor/physician IF you feel unwell. P302+P352:IF ON SKIN: wash with plenty of soap and water. P305+P351+P338:IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.