Stable sulfur atoms that have the same atomic number as the element sulfur, but differ in atomic weight. S-33, 34, and 36 are stable sulfur isotopes.

An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.

Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.

Chemical and physical transformation of the biogenic elements from their nucleosynthesis in stars to their incorporation and subsequent modification in planetary bodies and terrestrial biochemistry. It includes the mechanism of incorporation of biogenic elements into complex molecules and molecular systems, leading up to the origin of life.

Creation and development of bodies within solar systems, includes study of early planetary geology.

The inanimate matter of Earth, the structures and properties of this matter, and the processes that affect it.

Sulfur compounds in which the sulfur atom is attached to three organic radicals and an electronegative element or radical.

The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

Atomic species differing in mass number but having the same atomic number. (Grant & Hackh's Chemical Dictionary, 5th ed)

Inorganic salts of sulfuric acid.

The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)

A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)

Techniques for labeling a substance with a stable or radioactive isotope. It is not used for articles involving labeled substances unless the methods of labeling are substantively discussed. Tracers that may be labeled include chemical substances, cells, or microorganisms.

A great expanse of continuous bodies of salt water which together cover more than 70 percent of the earth's surface. Seas may be partially or entirely enclosed by land, and are smaller than the five oceans (Atlantic, Pacific, Indian, Arctic, and Antarctic).

Inorganic or organic compounds that contain sulfur as an integral part of the molecule.

A flammable, poisonous gas with a characteristic odor of rotten eggs. It is used in the manufacture of chemicals, in metallurgy, and as an analytical reagent. (From Merck Index, 11th ed)

The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.

Stable nitrogen atoms that have the same atomic number as the element nitrogen, but differ in atomic weight. N-15 is a stable nitrogen isotope.

Stable oxygen atoms that have the same atomic number as the element oxygen, but differ in atomic weight. O-17 and 18 are stable oxygen isotopes.

Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.

A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).

A highly toxic, colorless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant.

'Sulfur-containing amino acids' are a category of amino acids, the building blocks of proteins, that include methionine and cysteine, which contain sulfur atoms as part of their side chains, playing crucial roles in protein structure, enzyme function, and antioxidant defense.

Severe irritant and vesicant of skin, eyes, and lungs. It may cause blindness and lethal lung edema and was formerly used as a war gas. The substance has been proposed as a cytostatic and for treatment of psoriasis. It has been listed as a known carcinogen in the Fourth Annual Report on Carcinogens (NTP-85-002, 1985) (Merck, 11th ed).

Stable zinc atoms that have the same atomic number as the element zinc, but differ in atomic weight. Zn-66-68, and 70 are stable zinc isotopes.