Phosphorus Hydride

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The chemical element phosphorus is often used in fireworks but its most important application is as the starting material for organophosphorus compounds and fire resistant polymers. phosphorus hydride (PH), formed by the disproportionation of white phosphorus at elevated temperatures, is a poisonous and highly reactive gas that burns in air to form phosphine, with a foul odor.

The low vapor pressure of PH3 allows for its use in large scale reactions, although it must be handled carefully to avoid toxic effects. It is a key reactant in the production of metal phosphides by the reduction of the corresponding organophosphorus salts. The phosphorus hydride is also the starting material for the synthesis of many other organic compounds including the flame retardants hexachlorobenzene and tricloroethylene.

Recent Advances in Hydride Chemistry

A recently published paper describes the discovery of a two-dimensional phase of compressed “phosphine” with superconductivity below 30 K at 83 GPa. This phase is stabilized by layers of fluid hydrogen molecules that minimize Coulomb repulsion between adjacent 2D sheets of phosphorus atoms.

phosphorus hydride forms when white phosphorus is heated at high temperature in the presence of a catalyst such as magnesium bisphosphate. The reaction results in a mixture of phosphine and phosphoric acid, which can be further reacted to produce substituted phosphines.

phosphorus hydride is more electronegative than nitrogen, which makes it less able to expand its valence shell to hold more than eight electrons. This fact, along with the fact that phosphorus is more stable than nitrogen at higher temperatures, leads to the formation of an extensive array of compounds in which phosphorus has negative oxidation numbers. The radii of phosphorus and oxygen are comparable, so P-O double bonds are weaker than O-O double bonds.

The chemical element phosphorus is often used in fireworks but its most important application is as the starting material for organophosphorus compounds and fire resistant polymers. phosphorus hydride (PH), formed by the disproportionation of white phosphorus at elevated temperatures, is a poisonous and highly reactive gas that burns in air… Continue reading →

Optimizing Sample Preparation for Boron Neutron Capture Therapy

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Boron is a hard, brittle semimetal. It is lustrous black in crystalline form and brown in amorphous form. It combines with oxygen to form boron oxide (B2O3), boric acid (BHB) and other boride compounds. It is also used in pyrotechnic devices to produce a green flame and borosilicate glass. It is a useful neutron absorber in nuclear reactors. It is present in the form of borosilicate rods in pressurized water reactors for reactivity control and in sodium pentaborate for standby liquid control systems in boiling water reactors. It is also used as a chemical shim in fast breeder reactors and as a radiation shield.

In humans, the isotope boron 10 (B-10), which has a high thermal neutron capture cross section, can be used in so-called boron neutron capture therapy (BNCT). When injected into cancer cells, B-10 atoms absorb the slow neutrons from outside the body, releasing alpha particles that destroy the cell.

However, it is difficult to deliver enough boron 10 to cancer cells in a concentrated manner for this treatment to be practical. Furthermore, boron contamination is often an issue in B-10 doping in commercial-off-the-shelf (COTS) silicon microcontrollers due to its high neutron capture cross section. Therefore, it is critical to understand the kinetics of boron insertion into the dative carbene boron-boron bond and to accurately measure the concentration in cell cultures using techniques like secondary ion mass spectrometry (SIMS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). This paper describes the optimization of sample preparation for these two analytical methods on a variety of cell culture samples.

Boron is a hard, brittle semimetal. It is lustrous black in crystalline form and brown in amorphous form. It combines with oxygen to form boron oxide (B2O3), boric acid (BHB) and other boride compounds. It is also used in pyrotechnic devices to produce a green flame and borosilicate glass. It… Continue reading →

Barium Disc

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Barium is a white, chalky powder that mixes with water to make a liquid. It appears white on X-ray films and is used to visualize the insides of a body part, such as a digestive tract. The procedure is done with fluoroscopy, which produces a continuous X-ray movie of the area being examined. A radiologist watches the X-ray movie on a monitor and can immediately show the patient if an abnormality is present.

A barium small bowel follow through (sometimes called upper and lower gastrointestinal series) is an imaging test used to diagnose abnormalities of the esophagus, stomach, large intestine and/or small intestine. It involves filling the intestine with barium liquid while X-ray images are taken to detect ulcers and other inflammatory conditions, tumors, polyps, hernias, and strictures. The barium tablet (E-Z-DISK) disintegrates within 30 minutes of ingestion and the fragments pass through the esophagus without absorption.

In disc golf, the glide rating is a measure of how well a disc can maintain its distance on a flat trajectory. Glide is the product of lift and drag, with higher lift and lower drag resulting in a more stable flight. The Bohrium’s rounded rim allows for significantly less drag than other maximum speed drivers, allowing the disc to fly longer and more accurately.

Barium is also a component of spectroscopic windows and scintillator materials for detection of X-rays and gamma rays. It is an excellent choice for use in applications requiring high transparency from the ultraviolet to the infrared region, such as optical components like lenses.

Barium is a white, chalky powder that mixes with water to make a liquid. It appears white on X-ray films and is used to visualize the insides of a body part, such as a digestive tract. The procedure is done with fluoroscopy, which produces a continuous X-ray movie of the… Continue reading →

Molybdenum Fluoride Complexes

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Molybdenum is a major industrial metal and occurs naturally in various oxidation states as molybdenite. It is also recovered as a byproduct of copper and tungsten mining. As a metal it is relatively insoluble in organic solvents but readily forms complexes with alkali and rare earth fluorides. These compounds are of interest in many current technologies and applications, especially in oxygen-sensitive areas such as etching, metal production and synthetic organic chemistry.

The oxide fluorides of molybdenum are a useful starting point in synthesising molybdenum(VI) compounds, which have a wide range of uses in industry. In particular, the ionic hydrate MoF2(CO)3 is widely used as an oxygen carrier in molecular oxygen generators. In addition, the ionic hydrate of difluorotricarbonyl molybdenum (MoF2(CO)3) is a key component in high-power mid-infrared optical frequency combs.

In the solid phase, MoOF4 is polymeric with two cis fluoride bridges and a distorted octahedral molybdenum centre. In solution, it forms a range of complexes with N- and O-donor ligands. The X-ray structure of the six-coordinate complex [MoOF4(Ph3PO)] has been determined and is comparable to that of the molybdenum(VI) analogue tungsten(V) oxide fluoride, [WOF4(Ph3PO)].

The reaction of MoF4 with thf, Ph3PO, Me3PO, dmf or dmso in rigorously anhydrous conditions yields the corresponding complexes [MoOF4(L)], which are characterised by microanalysis, IR and 19F1H, 31P1H and 95Mo NMR spectroscopy. The complexes are moisture sensitive and upon evaporation in MeCN yield a mixture of the insoluble polymer and soluble Mo/O/F species.

Molybdenum is a major industrial metal and occurs naturally in various oxidation states as molybdenite. It is also recovered as a byproduct of copper and tungsten mining. As a metal it is relatively insoluble in organic solvents but readily forms complexes with alkali and rare earth fluorides. These compounds are… Continue reading →

The Chemical Formula For Aluminum Nitride

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Aluminum nitride, or AIN, is one of the post-transition metal nitrides and is an inorganic compound with chemical formula AlN. It has a crystal structure that is hexagonal and it is an electrical insulator in its natural state. However, it can be doped to allow it to behave as a semiconductor and has a wide band gap at room temperature that could potentially make it useful in deep ultraviolet optoelectronics.

It is a newer material in the technical ceramics family and was only discovered over 100 years ago, although it has been made into a commercially viable product with controlled properties within the last 20 years. Its thermal conductivity is nine times greater than alumina and it is used in several applications such as thermocouple insulators, evaporation boats, grinding media, and crystal growing crucibles. The market is expected to grow owing to its use in power electronics, and as a substitute for tungsten carbide in high-speed tools.

The structure of AlN is based on ionic bonds and therefore it does not exist as individual molecular units like water or other molecules do. Instead, an ionic compound has a large three-dimensional array of cations and anions arranged in a tetrahedral coordination. When writing the chemical formula for ionic compounds it is important to write the symbol of the metal cation and then the non-metal anion, crisscrossing their ion charges to make sure that the final formula is neutral. For example, zinc phosphate is composed of three zinc cations with 2+2+ charges balancing out two phosphate anions with 3-3- charges.

Aluminum nitride, or AIN, is one of the post-transition metal nitrides and is an inorganic compound with chemical formula AlN. It has a crystal structure that is hexagonal and it is an electrical insulator in its natural state. However, it can be doped to allow it to behave as a… Continue reading →

GaN Compound

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A binary III/V direct energy gap semiconductor, gallium nitride is the material of choice for blue and violet light-emitting diodes (LEDs). It has very high hardness and the wurtzite crystal structure makes it difficult to cleave or cut, which leads to long lifespans. GaN is also a good material for devices that require very high breakdown voltages, such as power field-effect transistors. Its low sensitivity to radiation makes it suitable for use in military and space applications.

Wide bandgap semiconductors such as GaN can be used to replace silicon-based power transistors because of their higher withstand voltages and much greater levels of resilience to heat. In addition, they are able to deliver the very high break down voltages required for microwave RF power amplifiers.

GaN can be produced on a variety of substrates using metal-organic chemical vapor deposition. However, the process is expensive, and it requires the use of expensive dopants such as magnesium. It is also a challenge to produce P-type gallium nitride, which is needed for devices that require complementary outputs, such as bipolar transistors, and for high-speed CMOS logic.

GaN-based devices have the potential to be used in a range of consumer electronics and industrial applications, as they can operate at higher temperatures and at higher currents than conventional silicon-based semiconductor devices. Additionally, they are much more efficient than silicon-based devices and can be produced at lower cost.

A binary III/V direct energy gap semiconductor, gallium nitride is the material of choice for blue and violet light-emitting diodes (LEDs). It has very high hardness and the wurtzite crystal structure makes it difficult to cleave or cut, which leads to long lifespans. GaN is also a good material for… Continue reading →

Zinc Granules

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Zinc is a metallic, bluish-white metal that is brittle at room temperature but becomes malleable when heated. It is used for many purposes, including galvanizing steel to protect it from rust; making brass; coating wire and other components; and in medicine and cosmetics. zinc granules are a form of the metal that is finely ground and more convenient to use than the chunky pieces of pure zinc. The granules are able to react more quickly with hydrochloric acid than pure zinc can due to its smaller particle size.

Pure zinc can be obtained by smelting it from its ores or from a zinc concentrate. To produce pure zinc from concentrates, it must be remelted in a special bath to separate out the iron-containing material called zinc dross. Once removed from the dross, the pure zinc is mixed with other elements such as aluminum to produce a mixture called the zinc blende. The zinc blende is then melted in a crucible to make pure zinc ingots.

When the ingots are exposed to hydrochloric acid, they react to form zinc chloride and hydrogen gas. This reaction is known as a single replacement reaction. The granules react more rapidly than pure zinc can because they contain copper, an impurity that acts as a catalyst and speeds up the rate of reaction. This is why zinc granules are preferred for laboratory preparation of hydrogen compared to the use of pure zinc powder.

Zinc is a metallic, bluish-white metal that is brittle at room temperature but becomes malleable when heated. It is used for many purposes, including galvanizing steel to protect it from rust; making brass; coating wire and other components; and in medicine and cosmetics. zinc granules are a form of the… Continue reading →

Sodium Nitrate Solution

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sodium nitrate solution is a colorless, odorless salt that dissolves in water. It is used in the manufacture of potassium nitrate, fertilizers, explosives and to preserve meats. Sodium nitrate is also useful in the production of high-strength glass and for the etching and purification of metals. It is a moderately strong oxidizer, toxic by ingestion and inhalation, and it promotes burning when exposed to flame.

It is also an excellent lubricant and fire-retardant. It is a common ingredient in fireworks. It is also used in the manufacture of the compound nitrous oxide, which is commonly known as laughing gas.

Nitrates and nitrites (such as those found in processed meat products) can cause heart disease. But they also prevent harmful bacteria from growing. This occurs because nitrates are converted to nitric oxide in our bodies, which causes blood vessels to dilate.

Research shows that low levels of nitrate ingestion are safe for humans. In fact, a healthy diet provides most of the nitrates people need to maintain cardiovascular health. But people should avoid nitrates from processed meats, which are linked to stomach, esophageal, lung and pancreatic cancers.

A good way to understand the safety of a chemical is to look up its Material Safety Data Sheets (MSDS) online. They contain detailed information, such as LD50 — the lethal dose for 50% of test animals. You can find the MSDS for most chemicals by entering their name into a web search engine.

sodium nitrate solution is a colorless, odorless salt that dissolves in water. It is used in the manufacture of potassium nitrate, fertilizers, explosives and to preserve meats. Sodium nitrate is also useful in the production of high-strength glass and for the etching and purification of metals. It is a moderately… Continue reading →

Lead-207 Isotope Ratios

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Lead is a toxic element with an extremely long environmental half-life. It is found in a wide variety of naturally occurring compounds, including the oxides: lead monoxide, PbO, in which lead is in the +2 oxidation state; lead dioxide, PbO2, in which it is in the +4 oxidation state; and trilead tetroxide, Pb(C2H3O2)2, which occurs as a yellow solid. In aqueous solution, it forms lead(II) ions and the water-soluble lead ion chelate, Pb(CH3COO)2.

Among the 43 known natural isotopes of lead (Pb), five are most important to geochemical research: 204Pb, 206Pb, 207Pb, and 208Pb. Of these, the last three are primordial nuclides; they are at the ends of decay chains originating in long-lived 238U, 235U, and 232Th isotopes.

The isotopic composition of lead in rocks depends on the amount of uranium and thorium present, so lead-isotope ratios are used to estimate the age of geological specimens. This information is also useful for the study of tectonic processes that affect the distribution of uranium and thorium in the Earth’s crust.

In the late 1960s, airborne particulates from burning leaded gasoline were analyzed for their organolead composition by gas chromatography with inductively coupled plasma-mass spectrometry. The lead isotope ratios of the different organolead species measured in these airborne samples from the same city exhibited considerable variability that could not be explained by analytical scatter. The results are illustrated in Figure 18.7.4 which shows the variation in d206Pb measured in published dispensed gasoline data versus the ALAS model curve (solid black). This is an illustration of the lead paradox described above.

Lead is a toxic element with an extremely long environmental half-life. It is found in a wide variety of naturally occurring compounds, including the oxides: lead monoxide, PbO, in which lead is in the +2 oxidation state; lead dioxide, PbO2, in which it is in the +4 oxidation state; and… Continue reading →

Titanium Carbide Hardness

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Titanium, tungsten, and titanium carbide are three of the most hard materials on the planet. All are very tough and scratch-resistant, which makes them great choices for jewelry, surgical implants, armor-piercing rounds, cutting tools, and other applications requiring high levels of wear resistance. However, each one has a slightly different level of hardness. Titanium is the softer of the three, while tungsten has the highest hardness and is also the most expensive.

Titanium carbide, known chemically as TiC, registers 9-9.5 on the Mohs scale and has the appearance of black powder with a face-centered cubic crystalline structure. It is most often combined with tungsten and cobalt in cemented carbide (CC) tools, but it is also used alone for heat-resistant parts.

In addition to its high strength and hardness, titanium carbide has good chemical stability. It does not change valence states during temperature changes and is resistant to corrosion by water, air, and oxygen. Its low coefficient of friction, especially when dry, provides excellent wear resistance.

When used in conjunction with tungsten carbide, titanium improves the toughness of the tool and enhances its wear resistance by protecting it from chipping. It is also useful for cutting extremely abrasive metals like high-nickel alloys, stainless steel, and hardened carbon steels. Ferro-TiC’s self-lubricating micrograins prevent pick-up and galling, which occurs when hard metals rub against each other in conditions of poor lubrication. This results in long part life, even when used in highly abrasive applications.

Titanium, tungsten, and titanium carbide are three of the most hard materials on the planet. All are very tough and scratch-resistant, which makes them great choices for jewelry, surgical implants, armor-piercing rounds, cutting tools, and other applications requiring high levels of wear resistance. However, each one has a slightly different… Continue reading →