Neodymium oxide was first isolated from a mixture of oxides called didymia. The element neodymium is the second most abundant lanthanide element in the igneous rocks of Earth's crust.
Neon (from the Greek word neos, meaning "new") is the second lightest of the noble gases. It forms no stable compounds with other elements.
Neptunium was discovered by the U.S. physicists Edwin M.
Neurochemistry refers to the chemical processes that occur in the brain and nervous system. The fact that one can read this text, remember what has been read, and even breathe during the entire time that these events take place relies on the amazing chemistry that occurs in the human brain and the nerve cells with which it communicates.
Many chemical compounds, some natural and some made by humans, show toxic effects in humans or other animals. Every toxin is harmful, but toxins that target the nervous system have been developed into chemical warfare agents, so the public concern about them is enhanced.
Neurotransmitters are chemical messengers produced by the nervous systems of higher organisms in order to relay a nerve impulse from one cell to another cell. The two cells may be nerve cells, also called neurons, or one of the cells may be a different type, such as a muscle or gland cell.
The need for better batteries is a recurring theme in the effort to reduce energy consumption and in the effort to make electricity increasingly portable. As the world depends more and more on portable devices and turns to electric vehicles to reduce pollution, it becomes important that lightweight, long-lived batteries be developed.
Nickel is a silver-white, lustrous metal. It was first isolated by Swedish chemist Axel Fredrik Cronstedt in 1751.
Nicotinamide is the most common form of the vitamin niacin. Nicotinamide is found in the body as part of nicotinamide adenine dinucleotide (NAD), an important cofactor of many enzymes involved in metabolism and the production of energy from sugars and fats.
Nicotinamide adenine dinucleotide (NAD) is the coenzyme form of the vitamin niacin. Most biochemical reactions require protein catalysts (enzymes).
Nicotine, C10H14N2, is a highly toxic, pale yellow alkaloid produced in tobacco plants in response to leaf damage. Nicotine is synthesized in the roots of tobacco plants in response to hormones released by damaged tissue, and it is then carried to the leaves, where it is stored in concentrations of between 2 percent and 8 percent by weight.
Niobium metal is typically gray or dull silver in color. It is one of the refractory metals along with tantalum, tungsten, molybdenum, and rhenium, due to its very high melting point.
Nitrogen is a gaseous element that is abundant in the atmosphere as the molecule dinitrogen (N2). Scottish chemist Daniel Rutherford, Swedish chemist Carl Wilhelm Scheele, and English chemist Henry Cavendish independently discovered the element in 1772.
The first claim for the discovery of the element nobelium was made in Sweden in 1957. However, neither American nor Soviet researchers could duplicate the original results, which are now known to have been interpreted incorrectly.
The noble gases, also known as rare or inert gases, form Group 18 of the Periodic Table, embedded between the alkali metals and the halogens. The elements helium, neon, argon, krypton, xenon, and radon are the members of this group.
The purpose of nomenclature in chemistry is to convey information about the material being described. The designation chosen should be unequivocal, at least within the limitations of the type of nomenclature adopted.
Norepinephrine (noradrenaline) belongs to a family of biological compounds called catecholamines. These compounds are synthesized in sympathetic neurons and in the adrenal glands.
Nuclear chemistry is the study of the chemical and physical properties of elements as influenced by changes in the structure of the atomic nucleus. Modern nuclear chemistry, sometimes referred to as radiochemistry, has become very interdisciplinary in its applications, ranging from the study of the formation of the elements in the universe to the design of radioactive drugs for diagnostic medicine.
Following the discovery of the neutron in the early 1930s, nuclear physicists began bombarding a variety of elements with neutrons. Enrico Fermi in Italy included uranium (atomic number 92) among the elements he bombarded which resulted in formation of nuclei that decayed by emission of negative β-rays.
Nuclear fusion is a reaction whereby two smaller nuclei are combined to form a larger nucleus. It results in the release of energy for reactions that form nuclei of mass number below 60, with the largest energy release occurring with the lightest nuclides.
Nuclear magnetic resonance (NMR) is one of the most useful analytical methods in modern chemistry. It is used to determine the structure of new natural and synthetic compounds, the purity of compounds, and the course of a chemical reaction as well as the association of compounds in solution that might lead to chemical reactions.
Nuclear medicine involves the injection of a radiopharmaceutical (radioactive drug) into a patient for either the diagnosis or treatment of disease. The history of nuclear medicine began with the discovery of radioactivity from uranium by the French physicist Antoine-Henri Becquerel in 1896, followed shortly thereafter by the discovery of radium and polonium by the renowned French chemists Marie and Pierre Curie.
Nucleic acids are a family of macromolecules that includes deoxyribonucleic acid (DNA) and multiple forms of ribonucleic acid (RNA). DNA, in humans and most organisms, is the genetic material and represents a collection of instructions (genes) for making the organism.
Nucelotides are the repeating building blocks of nucleic acids (which are polynucleotides or polymers of nucleotides). A nucleotide is made up of a heterocyclic base (a purine or pyrimidine), a cyclic sugar unit (ribose or deoxyribose), and a phosphate group.
Walther Hermann Nernst, born in Briesen, Prussia (now Wabrzezno, Poland), was a pioneer in the field of chemical thermodynamics in a wide range of areas. His most outstanding contributions were his laws for electrochemical cells and his heat theorem, also known as the third law of thermodynamics, for which he was awarded the Nobel Prize in chemistry in 1920.
Sir Isaac Newton was born on December 25, 1642, in Woolsthorpe, Lincolnshire, England. His father died shortly before he was born.
Alfred Bernhard Nobel was born in Stockholm, Sweden, on October 21, 1833, as the third of four sons to Immanuel and Andriette (Ahlsell) Nobel. That same year, his father, an engineer and builder, went bankrupt when barges full of building materials were lost at sea.
John Northrop shared the Nobel Prize in chemistry in 1946 with Wendell Stanley, awarded to them "for their preparation of enzymes and virus proteins in a pure form," and with James Sumner, "for his discovery that enzymes can be crystallized." Although Sumner had been the first, in 1926, to crystallize an enzyme (urease) and to aver that enzymes were proteins, Northrop did more than any other scientist to establish that pure enzymes are indeed proteins.