Element Properties atomic number 5 atomic weight 10.811 melting point 2,200 °C (4,000 °F) boiling point 2,550 °C (4,620 °F) specific gravity 2.34 (at 20 °C 68 °F) oxidation state +3 electron configuration 1 s 22 s 22 p 1 Properties, occurrence, and uses Pure crystalline boron is a black, lustrous; i.e., it conducts like a at high temperatures and is almost an at low temperatures. It is hard enough (9.3 on ) to scratch some abrasives, such as, but too brittle for use in tools. It about 0.001 percent by weight of ’s crust.
Boron occurs combined as, and (hydrated borates), the major commercial boron minerals, especially concentrated in the arid regions of, and as widely dispersed minerals such as, and. Sassolite—natural boric acid—occurs especially in. Boron was first isolated (1808) by French chemists and and independently by British chemist by heating boron oxide (B 2 3) with metal. The impure product, a brownish, was the only form of boron known for more than a century. Pure crystalline boron may be prepared with difficulty by reduction of its bromide or chloride (BBr 3, BCl 3) with on an electrically heated filament. Limited quantities of elemental boron are widely used to increase hardness in.
Added as the, it is present in many steels, usually in the range 0.001 to 0.005 percent. Boron is also used in the nonferrous-metals industry, generally as a deoxidizer, in -base alloys and high-conductance copper as a degasifier, and in castings to refine the grain. In the industry, small, carefully controlled amounts of boron are added as a doping agent to and to modify electrical conductivity. In the form of boric acid or, traces of boron are necessary for growth of many land plants and thus are indirectly essential for life. Typical effects of long-term boron deficiency are stunted, misshapen growth; vegetable “brown heart” and “dry rot” are among the disorders due to boron deficiency.
Boron deficiency can be by the application of soluble borates to the soil. In excess quantities, however, borates act as unselective herbicides. Of several species of plants growing in soil naturally abundant in boron has been reported. It is not yet clear what the precise role of boron in plant life is, but most researchers agree that the element is in some way essential for the normal growth and functioning of apical meristems, the growing tips of plant shoots.
Pure boron exists in at least four crystalline modifications or allotropes. Closed cages containing 12 boron atoms arranged in the form of an icosahedron occur in the various crystalline forms of elemental boron.
Glossary Group A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell. Period A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right. Block Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f). Atomic number The number of protons in an atom.
Electron configuration The arrangements of electrons above the last (closed shell) noble gas. Melting point The temperature at which the solid–liquid phase change occurs.
Boiling point The temperature at which the liquid–gas phase change occurs. Sublimation The transition of a substance directly from the solid to the gas phase without passing through a liquid phase. Density (g cm −3) Density is the mass of a substance that would fill 1 cm 3 at room temperature. Relative atomic mass The mass of an atom relative to that of carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus.
Where more than one isotope exists, the value given is the abundance weighted average. Isotopes Atoms of the same element with different numbers of neutrons. CAS number The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.
Glossary Atomic radius, non-bonded Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods. Covalent radius Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination. Electron affinity The energy released when an electron is added to the neutral atom and a negative ion is formed. Electronegativity (Pauling scale) The tendency of an atom to attract electrons towards itself, expressed on a relative scale.
First ionisation energy The minimum energy required to remove an electron from a neutral atom in its ground state. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge.
Isotopes Atoms of the same element with different numbers of neutrons. Key for isotopes Half life y years d days h hours m minutes s seconds Mode of decay α alpha particle emission β negative beta (electron) emission β+ positron emission EC orbital electron capture sf spontaneous fission ββ double beta emission ECEC double orbital electron capture. Glossary Data for this section been provided by the. Relative supply risk An integrated supply risk index from 1 (very low risk) to 10 (very high risk). This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores.
Crustal abundance (ppm) The number of atoms of the element per 1 million atoms of the Earth’s crust. Recycling rate The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply. Substitutability The availability of suitable substitutes for a given commodity. High = substitution not possible or very difficult. Medium = substitution is possible but there may be an economic and/or performance impact Low = substitution is possible with little or no economic and/or performance impact Production concentration The percentage of an element produced in the top producing country.
The higher the value, the larger risk there is to supply. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. The higher the value, the larger risk there is to supply. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Glossary Specific heat capacity (J kg −1 K −1) Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K. Young's modulus A measure of the stiffness of a substance.
It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain. Shear modulus A measure of how difficult it is to deform a material.
Cosmic Ray Spallation
It is given by the ratio of the shear stress to the shear strain. Bulk modulus A measure of how difficult it is to compress a substance.
It is given by the ratio of the pressure on a body to the fractional decrease in volume. Vapour pressure A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. Let's start with the boring bit. Boron is usually isolated as a brown, amorphous solid. I don't know anyone who thinks the element boron has anything interesting about it.
But its unexpected side starts to emerge when you look at some simple compounds of boron. Consider the nitride, for example - just the 2 elements at numbers 5 and 7 in the periodic table, but able to join forces to provide hard diamond or soft graphite-like structures, very similar to those of the 6 th element, carbon. Then there is the trifluoride - remember that acids were first classified as substances that could provide protons, but BF 3 is the archetypal Lewis acid, which doesn't have a proton in sight, yet is able to coordinate with lone pairs, allowing it to catalyse an array of reactions. It can achieve this chemistry because boron really does have two sides to it - it is set up to form 3 bonds with adjacent atoms, but even in this state, readily forms an extra bond in order to complete the 2 nd main shell of 8 electrons. But when it does this, it acquires a negative charge, and it can only regain neutrality by losing one of its bonds - it really does have a split personality. But the real interest, the 'skydiving', starts when we look at the trihydride of boron.
We'll return to this later on, as BH 3 has structural subtleties that will really take us into sexy territory. But at this stage we'll simply see how boron's schizophrenic side can be used to good effect - add BH 3 to an alkene, then throw in some alkaline hydrogen peroxide, and the oxygen first attaches to the boron, and then gets shuttled onto the adjacent carbon, all driven by this balance between 3- and 4-valent boron. This rather complicated reaction (mechanistically) is very reliable, and has been used for decades now as a simple way of turning alkenes into alcohols. Building on this idea, lots of clever variants allow one to introduce the alcohol very selectively, including my favourite of the reagent made by reacting borane with cycloocta-1,5-diene; the resulting dialkylborane is incredibly selective at attacking only the least substituted carbon of an alkene, and its often abbreviated schematically to a BH unit hanging down from two arcs, leading to its nickname as the parachute molecule. So much for skydiving - what about motorbikes. Well this bit is rather like seeing what appears to be a 50cc moped, only to find that it goes from 0-to-60 in 3.5 seconds. Let me explain - the name boron comes from the mineral borax, which is a salt of the a really uninspiring acid called boracic acid.
You can buy it from any pharmacist, and it's a mildly acidic antiseptic, and it essentially comprises a boron atom attached to three OH groups. And here's the surprise - you can fairly easily swap one OH for an aryl group, and you generate an aryl boronic acid capable of coupling to a whole range of aryl halides using palladium catalysis.
This was a long sought-after process that many had thought impossible in high yield, until a chemist called Suzuki (hence the motorbike connection) found that boron could solve the trick. And lastly to the sexy bit. I said that boron trihydride had a structural subtlety, and that is the fact that it was an 'impossible' molecule back in 1945, in that there was no known bonding that could account for its dimeric structure, or that of some related boron hydrides. And then in one of those 'Just William' sort of stories when a youngster gets the better of his elders, Christopher Longuet-Higgins, then an undergraduate at Cambridge, came up with the solution during a tutorial, publishing the landmark paper with his tutor whilst still only 20. Their explanation also predicted several new boron hydrides, which were duly discovered, as well as the fascinating field of boron cluster chemistry, in which the tri/tetra-valent schizophrenia of boron allows partner swaps and multiple bonding.
But I won't elaborate further - you'll have to find out for yourself. But remember, don't just judge elements by their first appearance - they may have hidden secrets and unexpected talents. Terms & Conditions Images © Murray Robertson 1999-2011 Text © The Royal Society of Chemistry 1999-2011 Welcome to 'A Visual Interpretation of The Table of Elements', the most striking version of the periodic table on the web. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site. Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images.
The RSC maintains this Site for your information, education, communication, and personal entertainment. You may browse, download or print out one copy of the material displayed on the Site for your personal, non-commercial, non-public use, but you must retain all copyright and other proprietary notices contained on the materials. You may not further copy, alter, distribute or otherwise use any of the materials from this Site without the advance, written consent of the RSC.
The images may not be posted on any website, shared in any disc library, image storage mechanism, network system or similar arrangement. Pornographic, defamatory, libellous, scandalous, fraudulent, immoral, infringing or otherwise unlawful use of the Images is, of course, prohibited. If you wish to use the Images in a manner not permitted by these terms and conditions please contact the Publishing Services Department If you are in any doubt, please ask. Commercial use of the Images will be charged at a rate based on the particular use, prices on application. In such cases we would ask you to sign a Visual Elements licence agreement, tailored to the specific use you propose. The RSC makes no representations whatsoever about the suitability of the information contained in the documents and related graphics published on this Site for any purpose.
All such documents and related graphics are provided 'as is' without any representation or endorsement made and warranty of any kind, whether expressed or implied, including but not limited to the implied warranties of fitness for a particular purpose, non-infringement, compatibility, security and accuracy. In no event shall the RSC be liable for any damages including, without limitation, indirect or consequential damages, or any damages whatsoever arising from use or loss of use, data or profits, whether in action of contract, negligence or other tortious action, arising out of or in connection with the use of the material available from this Site. Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise. We hope that you enjoy your visit to this Site. We welcome your feedback. Visual Elements images and videos © Murray Robertson 1998-2017.
Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014. Tables of Physical & Chemical Constants, 16th edition, 1995. Version 1.0 (2005), accessed December 2014. Dragoset, 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.
Uses and properties John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011. Thomas Jefferson National Accelerator Facility - Office of Science Education, accessed December 2014., accessed December 2014. Supply risk data Derived in part from material provided by the © NERC.
History text Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.
Podcasts Produced. Created by video journalist Brady Haran working with chemists at The University of Nottingham.
Boron Facts Boron (B) is a black, semi-metallic element with an atomic number of five and five protons in the nucleus. Its compounds have been used for thousands of years, but the element itself was not isolated until the early nineteenth century. Interesting Boron Facts: Sir Humphry Davy, Joseph-Louis Gay-Lussac, and Louis Jaques Thenard isolated the boron element by creating a reaction of boric acid with potassium in 1808. Boron is fairly rare in the solar system and makes up only 0.001% of the Earth's crust, but its naturally occurring compounds are quite common. Some common compounds of boron are borax, boric acid, colemanite, kernite, ulexite, and borates. Pure boron is extremely difficult to produce, even in laboratory conditions, because of its propensity to join with carbon. Historically, borax glazes have been used by far-reaching cultures as early as AD300.
Eighteenth century Florentines used it for medical purposes as sal sedativum. Boron is fairly hard, and together with carbon and nitrogen forms a superhard and highly heat-resistant compound commonly called heterodiamond. Boron has two naturally occurring stable isotopes, 11B (80.1%) and 10B (19.9%), which are commonly used in a number of industries. Both 10B and 11B possess nuclear spin, with the spin of 10B being 3 and that of 11B being 3/2. Boron is present in over 100 minerals on Earth but is difficult to prepare or study. Biologically, boron is present in the cell walls of plants and is therefore present in all foods made from plants.
There is a boron-based natural antibiotic called boromycin, a derivative of streptomyces. Building estimator software. Boron is used in a number of well-known cleaning agents in the compound form borax.
Another compound, boric acid, is lethal to insects but not harmful to mammals, and is therefore used in pesticides. Related Links: Boron Facts.
Boron is an important, and often underutilized, trace mineral naturally present in certain foods and also within the environment. Boron uses include the ability to help keep the skeletal structure strong by adding to density, preventing, treating conditions like, and improving strength and muscle mass. Boron is used by many athletes and bodybuilders because it’s believed to increase the body’s ability to produce and use, so it’s beneficial for recovering from exercise, and pains, and keeping bones strong. Additionally, boron is linked to improved function in some instances since it helps boost concentration, focus and the ability to learn new information. What are some other boron uses?
Boron is linked with helping prevent conditions, including:. Osteoporosis and weak or. Low concentration or “brain fog”.
Poor memory. Signs of aging on the skin. Worsened and PMS symptoms. Weak muscles. Stomach and digestive.
infection and infections. Eye infections Boron uses even include the ability to help animals suffering from pain. Horses, sheep and other domesticated animals that develop signs of arthritis are sometimes given boron supplements to ease pain and.
In fact, because levels of boron in foods are highly dependent on how healthy the soil is where the crops are grown, animals that graze on depleted soils low in boron usually have less muscle, and more bone and joint pain as they age than animals raised on boron-rich soils. How Do W e Get Enough Boron? Boron is naturally found in many whole foods, especially beans, nuts, whole grains and avocados, as well as fruits like berries, plums, oranges and grapes. It’s also found in water to some degree, although we get most of our boron from our diets. The type of boron we obtain from food is primarily boric acid, B(OH)3, which is naturally present only in plants. Researchers believe boron works to stabilize molecules within plants, including beneficial polysaccharides and sterols, although the exact way boron works in both plants and humans is still somewhat unknown. Another theory is boron helps and assists the body in handling other minerals like, and by producing necessary digestive enzymes.
While there’s still a lot to learn about this mineral, one of the most researched boron uses is its ability to increase levels in both healthy women and men, which is one reason it’s linked to healthy bones and fewer signs of age-related diseases like cognitive decline and arthritis. Recommended Daily Intake of Boron You can make sure you get enough boron by eating a varied diet of whole, real food sources. While exact levels of boron are still not exactly known (and vary a lot depending on where the food was grown), the USDA reports that most people usually consume enough boron to meet their needs and get most of their boron from these foods: coffee, apples, beans and potatoes.
Together, these foods are responsible for about 27 percent of the boron most people consume. Even though it’s believed that coffee and milk aren’t the best sources of boron — they might actually be somewhat low in boron compared to many legumes, vegetables and fruits — they were the top contributors in the American diet because of the high amount many people consume of them. Because there’s limited studies involving boron’s exact role in the body, the USDA and other authorities still haven’t established a clear biological function for boron in humans or a recommended dietary allowance. Instead, they’ve determined an “upper limit,” which means the amount many people consume and maintain their health without experiencing signs of deficiency or toxicity. The upper limits for boron depend on your age and gender and are as follows:.
1–3 years: 3 milligrams/day. 4–8 years: 6 milligrams/day. 9–13 years: 11 milligrams/day.
14–18 years: 17 milligrams/day. Adults 19–50 years: 20 milligrams/day. Pregnant women: 17–20 milligrams/day. Women who are breastfeeding: 20–25 milligrams/day.
Health Benefits of Boron 1. Increases Concentration and Brain Function Research shows low levels of boron can contribute to a sluggish brain, poor cognitive development, and trouble learning or retaining information. Boron is often thought of as a “ nutrient” because it can help with task performance, better motor control, attention and even short-term memory. When researchers compared the effects of low boron intake in healthy adults with higher intake, there was a significant increase in the proportion of low-frequency brain activity and a decrease in the proportion of higher-frequency activity in the group taking more boron. Results showed improvements in task performance on various cognitive and psychomotor tests in the group receiving more boron, including better response times, motor skills and manual dexterity, eye-hand coordination, attention, perception, and both short- and long-term memory. Helps Reverse Arthritis Boron plays an important role in the integration of calcium into the joint’s cartilage, which helps prevent joint deterioration and. Research shows people with lower boron concentrations in their bones and synovial fluid experience higher rates of arthritis than those with higher levels.
Other study observations show evidence that bones of patients using boron supplements are much harder to cut than those of patients not using supplements. According to some epidemiologic studies, in areas of the world where boron intake is lower (around one milligram or less/day) the incidence of arthritis is significantly higher than in areas where boron intake is higher (around three to 10 milligrams/day on average). Strengthen Bones Boron uses also include the ability to prevent bone loss by facilitating, the main mineral involved in bone mineralization, directly into the bones, where it helps prevent porous and weak bones from developing. Boron also protects bones because of its role in regulating estrogen function.
Additionally, studies show boron can help the body produce and use better, which is a crucial nutrient for healthy bone formation, in addition to many other things like immune function and cognitive processes. A study by the Department of Orthopedics at Red Cross Hospital in China found that boron supplements can increase bone formation and inhibit bone resorption, producing therapeutical protection against osteoporosis in animal studies.
History
When rats were fed a boron-deprived diet, they experienced spongy bones, bone loss in the femurs and lumbar vertebrae, and increased osteoporotic conditions. On the other hand, rats given high-boron supplements showed improvements in bone mass, bone thickness, bone volume and higher levels of estradiol (a hormone tied to bone health). Balances Hormones As a mineral that can help balance levels of sex in both women and men, including and testosterone, boron helps as well as PMS, and also for increasing fertility. In animal studies, boron depletion is linked with fertility problems and birth defects, which suggests that boron can play a role in healthy reproduction and fetus development. In two small studies by the U.S. Department of Agriculture, when menopausal women were first fed a diet that provided low levels of boron and then were fed a diet richer in boron, they experienced lower levels of calcium and magnesium loss through urine and elevated (but still considered healthy) levels of estrogen and testosterone.
Promotes Healthy Muscle Mass Certain vitamins and minerals are better absorbed and utilized by the body when boron levels are higher, which is important for building muscle, and preventing pain by recovering muscle-tissue tears following exercise. And because boron helps promote healthy testosterone production, it might lead to higher energy levels and quicker strength gains. Other research also shows that boron uses may including boosting athletic performance because it helps the brain think quickly, react better to stimulus and demonstrate hand-eye coordination, in addition to keeping bones and joints stronger and free from pain. This is one reason why boron appears in more and athletic supplements promising better results, although more research is still needed to confirm whether or not boron can definitely impact body composition and physical abilities without being combined with other factors. Prevents and Treats Yeast Infections Boron is an active ingredient in tablets used to treat yeast infections in women.
Boron, in the form of boric acid, is used as a natural alternative to messy over-the-counter yeast infection medicines or creams. Boric acid is considered safe and effective when inserted into the vagina to speed up healing of painful infections. According to results from a double-blind comparison study looking at the effects of boron compared to another type of commercial yeast infection cream (made from nystatin), boron was better able to cure yeast infections. Ninety-two percent of women had relief after seven to 10 days of boron treatment compared to 64 percent using the standard cream. Boron produced no unwanted side effects and was also self-made and much less expensive than the cream, leading researchers to conclude that boric acid is a natural fungistatic and can be a better, cost-effective option than “messy” vaginal creams.
Heals Skin and Prevents Infections Boron uses include acting as an astringent to help prevent or treat infections on the skin, so it’s useful for lowering redness, inflammation, pain and other signs of irritation. For the same reason, some people also use boron as a natural eye wash to help kill bacteria that can lead to sties and other infections. Fights Diabetes Animal studies show that low levels of boron can increase physiological effects tied to, including changes in blood glucose (sugar) levels and triglyceride concentrations. It appears that boron can help with the metabolism of carbohydrates and the production of insulin from the pancreas that better controls stable blood sugar levels, so in the future we might see that boron uses include acting as a treatment for forms of insulin resistance. Best Food Sources of Boron While a comprehensive list of boron content within common foods isn’t yet available, below are 14 of the highest sources of boron. Another fun fact about boron uses? Boron acts as a natural food preservative within foods.
Because boron helps diminish bacteria growth, it’s a natural way to prevent crops from spoiling, so during World War I and II it was added to foods to prolong their freshness and reduce food pathogens when refrigeration wasn’t always possible. (black, lima, kidney, snap peas, ). Artichokes. Berries. Cherries. Onions. Pecans.
Walnuts. Prunes/plums. Peaches. Apricots. Cocoa. Apples. Pears.
Grapes (and pure grape juice). Oranges. Coffee.
(organic, unpasteurized) Recipes High in Boron You can naturally increase your intake of boron by making some of these recipes that include boron-rich foods: INGREDIENTS:. 2 avocados, cubed. 1 red pepper, diced.
2 tablespoons red onions, diced. 3 garlic cloves, minced. 1/4 cup fresh, chopped. 2 teaspoons lemon juice. 6–8 romaine lettuce, roughly chopped DIRECTIONS: 1. Mix all ingredients in a bowl.
Scoop out approximates 1/2 cup into gluten-free wrap and roll. What Are Concerns and Interactions of Taking Boron?
Preparation Of Elemental Boron In The Laboratory
Boron is widely recognized as being very safe for consumption in both humans and animals. In fact, some farmers even treat soil with high levels of boron and give boron supplements to their livestock to reduce the effects of radiation in the environment.
Industrial boron uses include its ability to capture radioactivity within soils, ionizing it and reducing potential health risks like. Of course, like with all nutrients, very high levels can also cause potential problems. Boron toxicity isn’t a risk when consuming whole foods, but taking high doses of supplements can potentially become dangerous and cause reactions like, gastric discomfort, vomiting, skin problems, heart palpitations, anxiety and.
The National Institute of Health also warns consumers that boron supplements can be harmful to people with hormone-sensitive conditions like breast or prostate cancer, and uterine fibroids since it can increase estrogen levels. People with existing cases of kidney disease or liver disease should also use boron supplements very carefully and speak with a doctor first since these conditions can alter the way the body gets rid of excess boron and other minerals. As always, it’s best to get boron (and all other vitamins and minerals) from real whole foods whenever possible as opposed to supplements. How much boron is too much?
Lethal doses of boron are believed to be about 15 to 20 grams/day for adults and three to six grams/day for infants, although many studies find minimal or no toxicity at these levels or even higher. Read Next: From the sound of it, you might think leaky gut only affects the digestive system, but in reality it can affect more. Because Leaky Gut is so common, and such an enigma, I’m offering a free webinar on all things leaky gut.
Boron Atomic Number: 5 Symbol: B Atomic Weight: 10.811 Electron Configuration: He2s 22p 1 Word Origin: Arabic Buraq; Persian Burah. These are the Arabic and Persian words for. Isotopes: Natural boron is 19.78% boron-10 and 80.22% boron-11. B-10 and B-11 are the two stable isotopes of boron. Boron has a total of 11 known isotopes ranging from B-7 to B-17. Properties: The melting point of boron is 2079°C, its boiling/sublimation point is at 2550°C, the specific gravity of crystalline boron is 2.34, the specific gravity of the amorphous form is 2.37, and its valence is 3. Boron has interesting optical properties.
The boron mineral ulexite exhibits natural fiberoptic properties. Elemental boron transmits portions of infrared light. At room temperature, it is a poor electrical conductor, but it is a good conductor at high temperatures. Boron is capable of forming stable covalently bonded molecular networks. Boron filaments have high strength, yet are lightweight.
The energy band gap of elemental boron is 1.50 to 1.56 eV, which is higher than that of silicon or germanium. Although elemental boron is not considered to be a poison, assimilation of boron compounds has a cumulative toxic effect. Uses: Boron compounds are being evaluated for treating arthritis. Boron compounds are used to produce borosilicate glass. Boron nitride is extremely hard, behaves as an electrical insulator, yet conducts heat, and has lubricating properties similar to graphite.
Amorphous boron provides a green color in pyrotechnic devices.
Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |