月: 2023年1月

What Is Beryllium Oxide?

Beryllium oxide (BeO), known as beryllia, is a significant material in various high-temperature applications due to its exceptional chemical stability and high melting and boiling points. Its CAS number is 1304-56-9.

Uses of Beryllium Oxide

Its applications span from rocket tips and fuel chamber components to nuclear reactor moderators and neutron reflectors. Notably, beryllium oxide is utilized in environments requiring resistance to extreme temperatures and is a preferred ceramic material due to its high thermal conductivity (325 W/m-K), surpassing many metals like aluminum. It is essential in products needing insulation alongside heat dissipation, such as medical equipment, laser circuit boards, and semiconductor manufacturing tools.

Properties of Beryllium Oxide

As a white powder or colorless crystal, beryllium oxide exhibits a hexagonal wurtzite-type structure with a molecular weight of 25.01, melting point of 2,570°C, and boiling point of 3,900°C. Its density is 3.02 g/mL, and it shows minimal water solubility. While stable under normal conditions, it dissolves in concentrated sulfuric acid, hydrochloric acid, and hydrofluoric acid under specific conditions, forming various beryllium compounds.

Types of Beryllium Oxide

Available as both a reagent for research and development and an industrial ceramic material, beryllium oxide is offered in various grades and quantities, tailored to laboratory or industrial applications. Its versatility is evident in its range of strengths and thermal conductivities.

Reagent Products for Research and Development

For laboratory use, reagent products are supplied in practical quantities ranging from 5g to 500g, designed for ease of use and storage at room temperature due to their stability.

Industrial Ceramic Materials

As an industrial ceramic, beryllium oxide is prized for its excellent insulation properties and thermal conductivity. Potential users should consult with manufacturers for specific grades to meet their requirements.

Other Information on Beryllium Oxide

Synthesis of Beryllium Oxide

Beryllium oxide is synthesized through thermal decomposition of beryllium carbonate, beryllium nitrate, or beryllium hydroxide. Industrially, it is produced from beryllium sulfate, obtained by treating beryllium-containing materials with sulfuric acid, followed by decomposition with alkali at high temperatures.

Chemical Reaction of Beryllium Oxide

Despite its stability, beryllium oxide can react with concentrated sulfuric acid, hydrochloric acid, and hydrofluoric acid under high temperatures, leading to the formation of beryllium sulfate, beryllium chloride, and a fluorine complex, respectively.

What Is Bismuth Oxide?

Bismuth oxide is an inorganic compound, presented as a light yellow or yellowish-brown powder. It consists of bismuth and oxygen, with the chemical formula Bi₂O₃, a molecular weight of 465.96, and a CAS number of 1304-76-3. It is also known as bismuth (III) oxide.

Structure of Bismuth Oxide

Crystal Polymorphs of Bismuth Oxide

Bismuth oxide exists in five crystallographic polymorphs: α-Bi₂O₃ (monoclinic at room temperature), β-Bi₂O₃ (tetragonal at high temperatures), γ-Bi₂O₃ (body-centered cubic), and δ- and ε-Bi₂O₃ (both cubic). Its structure significantly differs from those of arsenic oxide (As₂O₃) and antimony oxide (Sb₂O₃).

Alpha and Beta Phases

The α phase features a complex arrangement of oxygen and bismuth layers, with bismuth atoms in distorted 6- and 5-coordination environments. The β phase resembles the fluorite structure.

γ, δ, and ε Phases

The γ phase is structurally similar to Bi₁₂SiO₂₀, with some bismuth sites occupied by silicon, described as Bi₁₂Bi_0.8O_19.2. The ε phase, akin to the α and β phases, acts as a perfectly aligned ionic insulator.

Properties of Bismuth Oxide

Bismuth oxide melts/solidifies at 820°C and boils at 1,890°C. It dissolves in dilute hydrochloric and nitric acids but is virtually insoluble in water. Its electronic conductivity transitions from p-type at room temperature to n-type between 550 and 650°C, depending on the oxygen partial pressure.

Uses of Bismuth Oxide

Synthetic Raw Materials

It serves as a catalyst and in the production of bismuth salts and rubber compounding agents, as well as in glazes and pigments.

Electronic Components

Bismuth oxide is crucial for manufacturing thermistors, varistors, capacitors, and permanent magnets. It is increasingly used as a lead substitute in electronics.

Dental Materials

In dentistry, bismuth oxide enhances the opacity of materials for x-rays. It is added to hydraulic silicate cements, improving the visibility of dental procedures under x-ray.

Other Information on Bismuth Oxide

Bismuth Oxide Manufacturing Process

Commercially, it is produced from bismuth subnitrate by dissolving bismuth in hot nitric acid, followed by precipitation with sodium hydroxide, or by heating bismuth hypocarbonate or bismuth hydroxide.

Reaction of Bismuth Oxide

It reacts with mineral acids to form bismuth salts and with carbon dioxide in water to form bismuth hypocarbonate, among other reactions.

Regulatory Information

Bismuth oxide is not subject to major domestic regulations, including the Fire Service Law and Poisonous and Deleterious Substances Control Law.

Handling and Storage Precautions

Key precautions include sealing the container tightly, storing in a cool, dark place, using protective gear, and ensuring proper ventilation and cleanliness after handling.

What Is Barium Oxide?

Barium oxide is an inorganic compound consisting of oxidized barium with the chemical formula BaO. It features a cubic crystal structure resembling the sodium chloride-type structure and appears as a white to light grayish-brown powder or mass. This compound is hygroscopic and dissolves in dilute hydrochloric acid, having a molecular weight of 153.33 and a CAS number of 1304-28-5.

It is classified under various regulations due to its hazardous nature, including being a Deleterious Substance, Packing Class 3 and a Poisonous and Noxious Substance under multiple laws, emphasizing the need for careful handling.

Barium oxide is related to other barium compounds such as barium hydroxide and barium peroxide, highlighting its importance in various chemical processes.

Uses of Barium Oxide

As a vital raw material, barium oxide is utilized in the production of glass, barium salts (e.g., barium chloride, barium sulfate, barium nitrate), and ceramics. Its role extends to the manufacturing of barium sulfate used in inks, plastics, cosmetics, and paints, owing to its chemical stability. Additionally, barium sulfate serves as a contrast agent in X-ray examinations. Barium oxide also plays a crucial role in the IT sector as a precursor for barium carbonate and is employed in synthetic chemistry as a base and drying agent.

Properties of Barium Oxide

With a melting point of 1,920°C and a boiling point of 2,000°C, barium oxide reacts vigorously with water to form barium hydroxide. This reaction is notably more intense and exothermic than that of calcium oxide. Due to its solubility, it is toxic in aqueous solutions and exhibits corrosive properties because of its basic nature. Barium peroxide can be synthesized from barium oxide through heating in air or oxygen, although it decomposes back to barium oxide at temperatures above 800°C.

Other Information on Barium Oxide

Synthesis of Barium Oxide

Barium oxide is produced by burning barium metal in oxygen or through the thermal decomposition of barium hydroxide and barium carbonate, requiring high temperatures characteristic of alkaline earth metal hydroxides and carbonates.

Characteristics of Barium

Barium, an alkaline earth metal with an atomic number of 56 and symbol Ba, gradually oxidizes in air to form barium oxide.

Characteristics of Barium Hydroxide

Dissolving barium oxide in water yields barium hydroxide, a hazardous reaction due to its intensity. Barium hydroxide, represented by the formula Ba (OH)₂, is a basic inorganic compound used in analytical chemistry for titration purposes.

Characteristics of Barium Peroxide

Barium peroxide forms from barium oxide upon oxygen absorption and decomposes back to barium oxide and oxygen when heated. This compound, useful as an oxidizer and bleaching agent, contributes a green coloration to flames in fireworks.

What Is Nickel Oxide?

Nickel oxide is a dark green powdered inorganic compound, soluble in hydrochloric acid but insoluble in water. It holds the CAS No. 1313-99-1 and is subject to various safety and environmental regulations, including being listed under the Safety and Health Law and the PRTR Law, among others.

Uses of Nickel Oxide

Utilized for its catalytic properties, nickel oxide is a key catalyst in hydrogenating fats, oils, and other organic compounds. It is also essential in the production of electron tubes, special steels, electronic materials, and as a coloring agent in ceramics. Additionally, it serves as a precursor for nickel salts in nickel plating processes.

Properties of Nickel Oxide

With a molecular weight of 74.69 and a melting point of 1,960°C, nickel oxide is antiferromagnetic at room temperature and exhibits basic oxide characteristics. It reacts with acids to form green hydrated nickel ions and reduces to metallic nickel when heated in hydrogen gas.

Structure of Nickel Oxide

Nickel oxide primarily exists as nickel (II) oxide (NiO), known for its sodium chloride-type structure and non-stoichiometric composition. Other forms, nickel oxide (III) and (IV), are also noted but less well-defined in structure and application.

Other Information on Nickel Oxide

1. Synthesis of Nickel (II) Oxide

Nickel (II) oxide is produced by pyrolyzing nickel (II) compounds, resulting in a pure green powder.

2. About Nickel (III) Oxide

Nickel (III) oxide, a grayish-black powder used in alkaline storage batteries, is produced by heating nickel (II) nitrate. Its exact composition and structure remain uncertain, with some literature suggesting it might be a form of nickel (II) oxide with an indeterminate ratio.

3. About Nickel (IV) Oxide

Nickel (IV) oxide, or nickel dioxide, is an oxidizing agent obtained by oxidizing nickel hydroxide. It is theorized to form through the adsorption of oxygen on nickel (II) oxide.

What Is Niobium Oxide?

Niobium oxide encompasses oxides of niobium, including common forms like niobium (II) oxide (NbO) and niobium (V) oxide (Nb₂O₅), known respectively as niobium monoxide and niobium pentoxide. Niobium oxide is not classified under the Fire Service Law or the Poisonous and Deleterious Substances Control Law.

Uses of Niobium Oxide

Niobium oxide’s high refractive index in visible light makes it ideal for compact camera lenses and single-lens reflex cameras, aiding in product miniaturization and weight reduction. Its corrosion and acid resistance broaden its applications to automotive glass, low-reflection films for displays, semiconductor materials, photocatalytic materials, laminated ceramic capacitors, and valve metals.

Properties of Niobium Oxide

1. Niobium (II) Oxide

A black solid with metallic conductivity, NbO is stable, nonflammable, insoluble in water and nitric acid but slightly soluble in hydrogen chloride, with a melting point of 1,937°C.

2. Niobium (V) Oxide

Appearing as a white powder, Nb₂O₅ is insoluble in water and most mineral acids except for hydrofluoric acid, soluble in alkalis, with a melting point of 1,512°C and a density of 4.60 g/mL.

Types of Niobium Oxide

Commercially, both niobium (II) and niobium (V) oxides are available, with niobium (V) oxide being the predominant form used in industrial and research applications.

1. Reagent Products

Niobium (V) oxide, or niobium pentoxide, is primarily marketed for R&D, available in various sizes for laboratory use. Niobium (II) oxide is also available but in smaller quantities.

2. Industrial Niobium Compounds

As an industrial compound, niobium (V) oxide is used in piezoelectric materials and optical single crystals, sold in large volumes like 20 kg metal pails.

Other Information on Niobium Oxide

1. Synthesis

Niobium (V) oxide can be synthesized from niobium (V) chloride hydrolysis, while niobium (II) oxide can be obtained by reducing niobium (V) oxide with hydrogen or through homogenization.

2. Chemical Reactions

Industrial processes can convert niobium (V) oxide to niobium (II) using aluminum or carbon, and niobium (V) chloride can be produced from niobium (V) oxide and thionyl chloride. Additionally, niobium oxychloride (NbOCl₃) reacts with carbon tetrachloride (CCl₄) to yield more NbOCl₃.

What Is Tantalum Oxide?

Tantalum oxide, also called tantalum pentoxide, is a white to almost white powder or mass of inorganic compound.

Tantalum oxide’s main composition, compositional information, and physical and chemical properties are “Chemical formula: Ta2O5,” “Molecular weight: 441.89,” “CAS registration number: 1314-61-0,” and “Decomposition temperature: 1470°C.” It is almost insoluble in water.

Tantalum oxide is mainly applied to “Hazardous and Noxious Substances to be Labeled” and “Hazardous and Noxious Substances to be Notified” under the Safety and Health Law, and No. 338 under Appended Table 9, Article 18-2 of the Enforcement Order of the same law.

Uses of Tantalum Oxide

Tantalum oxide are used as raw material for optical lenses because of its high refractive index in the visible light range and superior film stability in ion assisted deposition (IAD) compared to other materials with a high refractive index.

Tantalum oxide  arealso used as raw material for antireflective coatings and interference filters used in computer displays and automobile windshields.

Furthermore, as a compound of tantalum oxide, which is known for its high dielectric constant, tantalum oxide are widely used in Japan’s world-class field of “electronic ceramics,” including dielectrics for electrolytic capacitors.

What Is Cerium Oxide?

Cerium oxide is a white or light yellow powder inorganic compound.

It is composed of cerium and oxygen, and has the chemical formula CeO₂, molecular weight 172.11, and CAS number 1306-38-3. It is one of the rare earth oxides and is also called ceria. It has a melting point/freezing point of 2,600°C, a boiling point or first distillation point and boiling range of 3,285°C, and a density/relative density of 7.132. Regarding solubility, it is insoluble in hydrochloric acid andnitric acid and virtually insoluble in water.

Uses of Cerium Oxide

Cerium oxide has the same structure as fluorite, with 8-coordinated Ce⁴⁺ and 4-coordinated O^2-, and the space group is Fm3m (#225).

Lattice defects are produced by oxygen partial pressure and mechanical loading, and polaron formation by oxygen defects and electrons localized on cerium ions is particularly noteworthy. Due to its ionic conductivity, which increases with the number of oxygen defects and the diffusion rate of oxide ions, cerium oxide is a promising candidate for solid-state electrodes in solid oxide fuel cells (SOFC).

Applications of Cerium Oxide

1. Abrasives

Cerium oxide is used as a raw material for abrasives for glass, optical lenses, and cathode ray tubes. Abrasives made from cerium oxide not only shave the surface, but also react chemically with silicon dioxide, a major constituent of glass, to make the surface smoother. Traditionally, oxides such as iron oxide and zirconia were used, but these have been replaced by cerium oxide in rapid succession.

2. UV Scattering Agent

Cerium oxide is used as an ultraviolet scattering agent to prevent ultraviolet rays from glass and cathode ray tube coloration, and is also used as an additive in cosmetics to cut ultraviolet rays. It is attracting attention as a substitute for titanium dioxide and zinc oxide.

3. Catalyst

Cerium oxide is used as a catalyst for oxidation reactions due to its property of reversibly changing composition. Cerium oxide-doped thorium oxide is used in the luminous part of white gasoline lanterns, and heat is generated by the air oxidation of fuel gas over a cerium oxide catalyst. It is also used in sensors for three-way catalysts that break down exhaust gases in automobiles, helping to regulate the air-fuel ratio and reduce NOx and carbon monoxide.

4. Optical Materials

Cerium oxide is also used as a highly refractive material with a transmission wavelength range from visible light to the infrared region. It forms crystalline films, has excellent chemical and thermal stability, and is considered to be lattice-matched with silicon. It is also characterized by evaporation at relatively low temperatures among high refractive index materials that have visible light in the transmission wavelength range.

5. Others

Cerium oxide is also used as a raw material for battery anode materials and fine ceramics. It is also used as a decolorizer for glass and can change greenish divalent iron impurities into nearly colorless trivalent iron oxide. Due to its excellent ionic and conductive properties, it is also expected to be used as a mixed ion-electron conductor.

Other Information on Cerium Oxide

1. Cerium Oxide Manufacturing Process

Cerium oxide can be obtained from natural cerium produced as a mixture with other rare earth elements from bastnaesite and monazite. After extraction in a basic aqueous solution, an oxidizing agent is added and the pH is adjusted to separate the cerium. This method takes advantage of the low solubility of cerium oxide and the fact that other rare earth elements are not oxidized.

2. Legal Information

Cerium oxide is not regulated by any major domestic laws such as the Fire Service Law, Poisonous and Deleterious Substances Control Law, Industrial Safety and Health Law, and PRTR Law.

3.Handling and Storage Precautions

Precautions for handling and storage are as follows

• Seal the container tightly and store in a dry, cool, and dark place.
• Use only outdoors or in well-ventilated areas.
• Take care not to scatter dust.
• Wear protective gloves and glasses when using.
• Wash hands thoroughly after handling.
• In case of skin contact, wash with soap and water.
• In case of eye contact, rinse cautiously with water for several minutes.

What Is Tin Oxide?

Tin oxide, appearing as a black-gray or black crystalline powder, is an inorganic compound with diverse applications.

With the chemical formula SnO and a molecular weight of 134.71, tin oxide melts at 1,080℃. It is governed by the Industrial Safety and Health Law, designated as a Hazardous and Noxious Substance for labeling and notification, without implications from laws like the Fire Service Law.

Uses of Tin Oxide

As a versatile compound, tin oxide serves as a reducing agent, a catalyst base, and in organic synthesis. It contributes to pigments, ferrous tin salts production, and tin plating replenishment. Additionally, it stabilizes PVC, preventing degradation over time—a crucial aspect for materials used in daily products and infrastructure.

Properties of Tin Oxide

Tin oxide manifests in several forms, including tin (II) oxide with a stable dark blue or metastable red state, reflecting tin’s +2 oxidation state.

Structure of Tin Oxide

The black α-SnO variant displays a tetrahedral PbO layer structure, mirroring the rare mineral lomarkite. Its asymmetry, influenced by the anti-bonding interaction between tin’s 5s orbital and oxygen’s 2p orbital, leads to an electronic band gap between 2.5 and 3 eV.

Other Information on Tin Oxide

1. Reactivity of Tin Oxide (II)

Tin (II) oxide reacts vividly in air, transforming into tin (IV) oxide with a dark green flame, and undergoes disproportionation in inert atmospheres. Its amphoteric nature allows reactions with both acids and bases, forming various tin salts and complexes, and contributes to copper red glass production.

2. Synthesis of Tin Oxide (II)

Dark blue tin (II) oxide is synthesized from tin (II) oxide hydrate via alkaline reaction, while red tin (II) oxide emerges from ammonia-treated tin (II) salts. Tin (II) oxide also derives from tin (II) oxalate decomposition in controlled, airless conditions.

3. About Tin Oxide (IV)

Tin (IV) oxide, or tin dioxide, SnO₂, is an antimagnetic amphoteric oxide. As a colorless powder, it forms a rutile-type structure, rendering it an oxygen-deficient n-type semiconductor. Tin (IV) oxide hydrates, varying in water content by particle size, illustrate the compound’s adaptability.

What Is Zirconium Oxide?

Zirconium oxide, an odorless white inorganic compound, is recognized for its significant properties and applications.

It is classified under domestic laws and regulations as a hazardous and toxic substance to be labeled and to be notified under the Safety and Health Law, yet not under other major regulations such as the Fire Service Law.

Uses of Zirconium Oxide

Zirconium oxide’s unique properties lend it to diverse applications:

• High Melting Point, Heat Resistance, and Chemical Erosion Resistance: Used in manufacturing cutting tools, refractory materials, and more.
• Hardness and Durability: Applied in dental materials, ceramic knives, and jewelry as imitation diamonds.
• Oxygen Ion Conductivity: Essential for solid electrolyte fuel cells.

Known for its extreme hardness, often compared to diamonds, zirconium oxide is about ten times harder than common ceramics. It is also utilized in electronic components like piezoelectric elements and ceramic capacitors, and as an additive in optical glass and quasi-drugs like catalysts and cosmetics.

Characteristics of Zirconium Oxide

Zirconium oxide, a ceramic material with the chemical formula ZrO₂, features a melting point of 2715°C, boiling point of 4300°C, density of 5.68 g/cm³, and a refractive index of 2.13.

It boasts low thermal conductivity, heat resistance, corrosion resistance, and high strength, but can degrade with temperature-induced structural changes.

Zirconium oxide transitions from a monoclinic structure at room temperature to tetragonal and cubic structures with increased temperature. Stabilizers like yttrium oxide (Y₂O₃), calcium oxide (CaO), cerium oxide (CeO₂), and magnesium oxide (MgO) help maintain a stable cubic crystal structure at room temperature, enhancing its conductivity of oxygen ions.

Other Information on Zirconium Oxide

1. Production Methods

Zirconium oxide is produced mainly through wet and dry refining from ores like zircon and haddelite. Wet refining involves melting ores with caustic soda, decomposition with hydrochloric acid, followed by calcination of zirconium hydroxide to produce zirconium oxide powder. Dry refining entails crushing the ore, removing impurities, and ore dressing to yield pure zirconium oxide.

2. Comparison with Zirconium

Unlike metallic zirconium, zirconium oxide is a ceramic bonded by strong covalent bonds, granting it superior corrosion resistance, hardness, and heat resistance due to its high melting point and strong bond formation.

What Is Cobalt Oxide?

Cobalt oxide, also recognized as tricobalt tetroxide, appears as a grayish-black or black powder. It has a chemical formula of Co₃O₄, a molecular weight of 240.80, and a CAS number of 1308-06-1. With a melting point of 895°C, it is insoluble in water but soluble in hydrochloric acid and concentrated alkali.

This compound is regulated under various laws and regulations due to its hazardous nature, including the PRTR Law and the Air Pollution Control Law.

Uses of Cobalt Oxide

As an oxidizer and catalyst, cobalt oxide is crucial for producing cobalt salts and serves as a pigment in ceramics and glass. It is instrumental in manufacturing cathode materials for lithium batteries, enamel, and as an additive in animal feed.

Properties of Cobalt Oxide

Cobalt oxide compounds vary by cobalt’s oxidation state, including cobalt (II) oxide, cobalt (III) oxide, and cobalt (II, III) oxide, with Co^IICo^III₂O₄ representing the mixed-valence compound.

1. Cobalt (II) Oxide

With the formula CoO, cobalt (II) oxide is a red to yellow-green crystal or black to gray powder, used in blue glazes and for synthesizing cobalt (II) salts. It forms by reacting cobalt with water vapor or decomposing cobalt oxide (II, III) at high temperatures.

2. Cobalt (III) Oxide

This blackish-brown powder, Co₂O₃, forms by reacting cobalt (II) nitrate with sodium hypochlorite, used as a catalyst and oxidizing agent.

Structure of Cobalt Oxide

The tricobalt tetroxide, or cobalt (II, III) oxide, exhibits a spinel-type structure, with Co²⁺ ions in tetrahedral sites and Co³⁺ ions in octahedral sites of the oxide ion lattice.

Other Information on Cobalt Oxide

1. Synthesis of Cobalt (II, III) Oxide

Produced by heating cobalt (II) oxide in air, it transitions to more stable forms at temperatures above 900°C.

2. Uses of Cobalt (II) Oxide

Historically significant as a pigment in ceramics, cobalt (II) oxide creates the deep blue known as cobalt blue. It is also essential in producing magnetic and battery materials and as a catalyst in oxidation reactions.