PRODUCTS

CADMIUM OXIDE

CAS NUMBER: 1306-19-0

EC NUMBER: 215-146-2

MOLECULAR FORMULA: CdO

MOLECULAR WEIGHT: 128.41

IUPAC NAME: oxocadmium

Cadmium Oxideoccurs naturally as the rare mineral monteponite.
Cadmium Oxide can be found as a colorless amorphous powder or as brown or red crystals.
Cadmium Oxide is an n-type semiconductor with a band gap of 2.18 eV (2.31 eV) at room temperature (298 K)

Production and Structure:
Since cadmium compounds are often found in association with zinc ores, cadmium oxide is a common by-product of zinc refining.
Cadmium Oxide is produced by burning elemental cadmium in air.

Pyrolysis of other cadmium compounds, such as the nitrate or the carbonate, also affords this oxide.
When pure, Cadmium Oxide is red, but CdO is unusual in being available in many differing colours due to its tendency to form defect structures resulting from anion vacancies.
Cadmium oxide is prepared commercially by oxidizing cadmium vapor in air.

Cadmium Oxide is used in:
-cadmium plating baths
-electrodes for storage batteries
-cadmium salts
-catalyst
-ceramic glazes
-phosphors
-nematocide

Major uses for Cadmium Oxide are as:
-an ingredient for electroplating baths
-optoelectronic devices
-in pigments

Transparent Conductor:
Cadmium Oxide is used as a transparent conductive material, which was prepared as a transparent conducting film as early as 1907 by Karl Baedeker.
Cadmium Oxide in the form of thin films has been used in applications such as:

-photodiodes
-phototransistors
-photovoltaic cells
-transparent electrodes
-liquid crystal displays
-IR detectors
-anti reflection coatings

Cadmium Oxide microparticles undergo bandgap excitation when exposed to UV-A light and is also selective in phenol photodegradation

Cadmium Plating:
Most commercial electroplating of cadmium is done by electrodeposition from cyanide baths.
These cyanide baths consist of cadmium oxide and sodium cyanide in water, which likely form cadmium cyanide and sodium hydroxide.
A typical formula is 32 g/L cadmium oxide and 75 g/L sodium cyanide.
The cadmium concentration may vary by as much as 50%.
Brighteners are usually added to the bath and the plating is done at room temperature with high purity cadmium anodes

Reactivity:
Cadmium Oxide is a basic oxide and is thus attacked by aqueous acids to give solutions of [Cd(H2O)6]2+.
Upon treatment with strong alkaline solutions, [Cd(OH)4]2− forms.
A thin coat of Cadmium Oxide forms on the surface of cadmium in moist air at room temperature.
Cadmium will oxidize at room temperatures to form CdO.
Cadmium vapor and steam will form CdO and hydrogen in a reversible reaction

Cadmium Oxide is a component of:
-silver alloys
-phosphors
-semiconductors
-glass
-ceramic glazes

Cadmium Oxide appears as brown crystals or brown amorphous powder.
Cadmium Oxide used as an electroplating chemical and in the manufacture of cadmium electrodes.
Cadmium Oxide Formerly used by veterinarians

Absorption, Distribution and Excretion:
Cadmium is a metallic impurity in various minerals.
The two main cadmium exposure sources in general population are food and tobacco smoking.
Cadmium is a cumulative toxic substance whose half-time for elimination is about 20 to 40 years and it is mainly stored in the liver and kidneys.

Inhalation of Cadmium Oxide fumes may cause inhalation fevers or chemical pneumonitis.
Cadmium chronic poisoning causes mainly renal tubulopathy and could be the cause of osteomalacia and diffuse osteoporosis.
The most relevant biological index exposure is the urinary cadmium.
According to literature, no chelating agent can be still used in human cadmium poisonings.

Use and Manufacturing:
High purity Cadmium Oxide is used as a second polarizer (in addition to silver oxide) in silver-zinc storage batteries
Oxidation of the sulfide or sulfite under carefully controlled oxidizing atmospheres at high temperature. An alternate method involves treatment of:
-powdered cadmium nitrate
-halide
-oxide
-or carbonate with dimethyl sulfate

The hydrated bromide is prepared by dissolution of:
-cadmium carbonate
-oxide
-sulfide
-or hydroxide in hydrobromic acid

Cadmium chloride is produced by reaction of molten cadmium and chlorine gas at 600 °C or by dissolving cadmium metal or the oxide in hydrochloric acid, subsequently vaporizing the solution.

OTHER APPLICATIONS OF CADMIUM OXIDE:

-Agricultural products (non-pesticidal)

-Batteries

-Building/construction materials not covered elsewhere

-Electrical and electronic products

-Metal products not covered elsewhere

-Paints and coatings

-Plastic and rubber products not covered elsewhere

Methods of Manufacturing:
Cadmium Oxide is produced by evaporation of cadmium metal and oxidation of the vapor.
Cadmium Oxide can also be obtained by thermal decomposition of cadmium nitrate or carbonate or by oxidation of molten cadmium by an oxidizing agent.
Commercial Cadmium Oxide should be completely soluble in sodium cyanide solution and contain no heavy-metal or sulfur impurities.
Pure Cd metal is melted and then vaporized whereupon air is blown through the hot vapor, oxidizing the cadmium and carrying the product to a baghouse.
The resultant oxide (particle size controlled by the /air to cadmium/ ratio) is calcined at 550 °C to ensure uniform properties.

Some fume and dust from welding processes may contain cadmium or cadmium oxide compounds.
The specific form and concentration of cadmium present are dependent on the composition of:

-the filler metal
-base metals
-metal coatings
-atmosphere
-flux
-welding process

Cadmium Oxide is Insoluble in water
Cadmium Oxide reacts violently with magnesium.
Cadmium Oxide Mixtures with magnesium explode when heated.

Most important cadmium compound is Cadmium Oxide, CdO.
Cadmium Oxide is a brown powder produced by burning cadmium vapor in air
Cadmium Oxide provides a convenient starting material for the production of most other cadmium salts.
Another compound of some economic value is cadmium sulfide, CdS.
Generally produced by treating cadmium

Cadmium Oxide is an inorganic compound with the chemical formula CdO.
Cadmium Oxide crystallizes in cubic rocksalt lattice with anion centers and octahedral cation.
Cadmium Oxide occurs naturally in the rare mineral monteponite.
Cadmium Oxide can be found as brown or red crystals or colorless amorphous powder.
Cadmium Oxide is an n-type semiconductor produced by burning elemental cadmium in air.

Applications:
Cadmium Oxide finds applications in the following:

-Electrodes for storage batteries
-Ceramic glazes
-Electroplating baths
-Pigments
-Cadmium salts
-Catalysts
-Nematocide

Cadmium Oxide (CdO) is a semiconducting material with high conductivity which isoptically transparent in the electromagnetic spectra.
Cadmium Oxidehas a direct bandgap of 2.28 eV
Cadmium Oxide can form a single crystal material by metal organic vapor phase epitaxy (MOVPE) growth.

Cadmium Oxide can be used in the synthesis of cadmium selenide quantum dots for potential applications in photocatalysis.
Cadmium Oxide is used as a transparent conducting oxide (TCO) which can further be used in a variety of opto-electronic devices.
Cadmium Oxide (CdO) is a unique chemical which is of both semiconductor and piezoelectric characteristics.

Cadmium Oxide is Brown crystals or brown amorphous powder. Used as an electroplating chemical and in the manufacture of cadmium electrodes.
Cadmium Oxide is a component of silver alloys, phosphors, semiconductors, glass and ceramic glazes.
Cadmium Oxide Formerly used by veterinarians to kill worms and parasites.

Cadmium Oxide is an inorganic compound with the formula CdO.
Cadmium Oxide is one of the main precursors to other cadmium compounds.
Cadmium Oxide crystallizes in a cubic rocksalt lattice like sodium chloride, with octahedral cation and anion centers.
Cadmium Oxide occurs naturally as the rare mineral monteponite.
Cadmium Oxide can be found as a colorless amorphous powder or as brown or red crystals.

Cadmium Oxide is used in:

-ceramic glazes
-cadmium electroplating baths
-pigments
-phosphors
-electrodes for storage batteries
-cadmium salts
-heterogeneous catalysis for dehydrogenation
-silver-zinc storage batteries
-Teflon
-phosphors
-semiconductors
-silver alloys
-glass
-nematocides
-ascaricides
-catalysts
-electroplating
-ceramic glazes
-PVC heat stabilizers

Cadmium Oxide is a basic conducting material used to prepare transparent conducting films, which finds use in phototransistors, liquid crystal displays, photodiodes, photovoltaic cells, and antireflection coatings.
Electrodeposited Cadmium Oxide films have excellent electrocatalytic activity towards many organic compounds, ozone and oxygen evolution.
Cadmium Oxide is selective in phenol photodegradation. Glassy carbon electrode coated with cadmium oxide film has been used to develop a sensitive and rapid assay method for penicillamine.

Cadmium Oxide is Stable under ordinary conditions.
Cadmium Oxide is Hygroscopic.
A thin coat of Cadmium Oxide forms on the surface of cadmium in moist air at room temperature.

Cadmium Oxide (CdO) may be in the form of a white amorphous powder or as red or brown crystals
Cadmium Oxide is formed when cadmium is burned or heated
Combined with an alkali-metal cyanide in baths for cadmium electroplating

Cadmium Oxide is an inorganic compound.
Cadmium Oxide is one of the main precursors to other cadmium compounds.
Cadmium Oxide crystallizes in a cubic rock salt lattice like sodium chloride, with octahedral cation and anion centers.
Cadmium Oxide is produced by burning elemental cadmium in air.

Cadmium fume (as Cd) is fi nely divided solid particles dispersed in air.
Cadmium Oxide forms brownish-red crystals or a yellow to dark brown amorphous powder.
Occurs in two forms, alpha form—a colorless amorphous powder, and beta form—a reddish-brown crystal;

-density 6.95 g/cm3 (alpha form) and 8.15 g/cm3 (beta form);
-decomposes on rapid heating at 900°C;
-sublimation temperature 1,559°C;
-insoluble in water and alkalis;
-dissolves in mineral acids

This is used for cadmium plating baths, electrodes for batteries (cells), ceramic glazes, and insecticides.
Cadmium Oxide is a deadly poison and carcinogen
Cadmium Oxide is used as an electroplating chemical, catalyst, component of semiconductors, and starting material for PCV heat stabilizers; in glass and ceramic glazes; for production of cadmium electrodes in storage batteries; and in other applications.
Cadmium Oxide is manufactured commercially by distilling cadmium metal from graphite retort and allowing vapor to react with air.

Preparation:
Cadmium Oxide is prepared by the reaction of cadmium vapor with oxygen.
The metal is first melted in a steel retort and transported into a heated chamber where it is vaporized.
The vapor is reacted with air, and the cadmium oxide formed is collected in a bag house.
The particle size of the product depends on the ratio of air to cadmium vapor.
The oxide may be further purified and particles of uniform size may be obtained by calcination at low red heat.

Cadmium Oxide also may be prepared by several other routes starting with various cadmium salts.
The compound can be made by thermal decomposition of cadmium carbonate or cadmium hydroxide:

CdCO3 → CdO + CO2
Cd(OH)2 → CdO + H2O

Similar thermal decomposition of cadmium nitrate or sulfate would yield the oxide.
Cadmium oxide also may be made by high temperature oxidation of cadmium sulfide:
2CdS + 3O2 → 2CdO + 2SO2

Finely divided oxide may be obtained by pyrolysis of cadmium salts of carboxylic acids, such as cadmium formate or oxalate.
(COOH)2Cd → CdO + H2O + 2CO
(COO)2Cd → CdO + CO2 + CO

PHYSICAL PROPERTIES OF CADMIUM OXIDE:

-Molecular Weight: 128.41

-Exact Mass: 129.898280

-Monoisotopic Mass: 129.898280

-Topological Polar Surface Area: 17.1 Å²

-Physical Description: DryPowder

-Color: Brown

-Form: Cubic Crystals

-Odor: Odorless

-Boiling Point: 1559 °C

-Melting Point: 900–1000 °C

-Solubility: soluble in dilute acid,slowly soluble in ammonium salts,insoluble in alkalies

-Solubility in water: 4.8 mg/L (18 °C)

-Density: 8.15 g/cm3(crystalline)

-Vapor pressure: 0.13 kPa (1000 °C)

-Decomposition: 900-1000 °C (amorphous)

Cadmium Oxide is used in cadmium plating baths, electrodes for storage batteries, cadmium salts, catalyst, ceramic glazes, phosphors, and nematocide, used as an ingredient for electroplating baths, pigments, transparent conductive material.
Cadmium Oxide is also used as chemical raw material for glass and ceramic industry.
Cadmium Oxide comes as a reddish-brown powder, odorless, with a purity of 99% minimum.
Cadmium Oxide is poorly soluble in water.

Cadmium Oxide is insoluble in water and alkalis, but soluble in acids and ammonium salts.
Cadmium Oxide reacts violently with magnesium.
Cadmium Oxide is used in electronics as a transparent conductor.
Cadmium Oxide is an inorganic compound with the formula CdO.
Cadmium Oxide is one of the main precursors to other cadmium compounds
Cadmium Oxide crystallizes in a cubic lattice like sodium chloride, with octahedral cation and anion centers

CHEMICAL PROPERTIES OF CADMIUM OXIDE:

-Hydrogen Bond Donor Count: 0

-Hydrogen Bond Acceptor Count: 1

-Rotatable Bond Count: 0

-Heavy Atom Count: 2

-Formal Charge: 0

-Complexity: 2

-Isotope Atom Count: 0

-Defined Atom Stereocenter Count: 0

-Undefined Atom Stereocenter Count: 0

-Defined Bond Stereocenter Count: 0

-Undefined Bond Stereocenter Count: 0

-Covalently-Bonded Unit Count: 1

-Compound Is Canonicalized: Yes

-Refractive Index: 2.49

-Thermal conductivity: 0.7 W/m·K

-Heat capacity (C): 43.64 J/mol·K

-Std molar entropy (So298): 55 J/mol·K

-Std enthalpy of formation (ΔfH⦵298): −258 kJ/mol

-Gibbs free energy (ΔfG˚): -229.3 kJ/mol

Other Experimental Properties:
-Cadmium Oxide Changes color on heating
-Cadmium Oxide is The red-brown crystalline form
-Cadmium Oxide is soluble in acids and alkalies
-Cadmium oxide is an n-type semiconductor with an energy gap of 222 kJ/mol (53 kcal/mol)

STORAGE OF CADMIUM OXIDE:

Cadmium Oxide should be stored in a moisture-free environment.
Cadmium Oxide should be stored in dry containers.
Cadmium Oxide should be kept in an inert atmosphere.

Cadmium Oxide should be stored in closed containers without contact with air.
Cadmium Oxide should be kept in a ventilated clean environment.

Cadmium Oxide should be stored away from reactive substances.
Cadmium Oxide should be stored separately from food and feedstuffs. It should be stored in an area without drainage or sewer access.
Cadmium Oxide should be kept away from substances with which it can react, especially magnesium.

SYNONYMS:

Cadmium oxide (CdO)
Cadmium fume
Cadmium monoxide
Aska-Rid
Cadmium oxide, 99%, pure
Kadmu tlenek [Polish]
Kadmu tlenek
Cadmium(II) oxide
CADMIUM FUME (AS Cd)
Cadmium oxide fume
Cadmium oxide brown
Cadmium oxide [Cadmium and cadmium compounds]
Cadmium oxide, puriss., 99.0%
Cadmium oxide, 99.998% (metals basis)
Cadmium oxide, >=99.99% trace metals basis
Cadmium oxide, powder, 99.5% trace metals basis