SALT(redirected from buffer salt)
Also found in: Dictionary, Thesaurus, Medical.
SALT, acronym for Strategic Arms Limitation Talks
salt, chemical compound
Characteristics and Classification of Salts
The most familiar salt is sodium chloride, the principal component of common table salt. Sodium chloride, NaCl, and water, H2O, are formed by neutralization of sodium hydroxide, NaOH, a base, with hydrogen chloride, HCl, an acid: HCl+NaOH→NaCl+H2O. Most salts are ionic compounds (see chemical bond); they are made up of ions rather than molecules. The chemical formula for an ionic salt is an empirical formula; it does not represent a molecule but shows the proportion of atoms of the elements that make up the salt. The formula for sodium chloride, NaCl, indicates that equal numbers of sodium and chlorine atoms combine to form the salt. In the reaction of sodium with chlorine, each sodium atom loses an electron, becoming positively charged, and each chlorine atom gains an electron, becoming negatively charged (see oxidation and reduction); there are equal numbers of positively charged sodium ions and negatively charged chloride ions in sodium chloride. The ions in a solid salt are usually arranged in a definite crystalline structure, each positive ion being associated with a fixed number of negative ions, and vice versa.
A salt that has neither hydrogen (H) nor hydroxyl (OH) in its formula, e.g., sodium chloride (NaCl), is called a normal salt. A salt that has hydrogen in its formula, e.g., sodium bicarbonate (NaHCO3), is called an acid salt. A salt that has hydroxyl in its formula, e.g., basic lead nitrate (Pb[OH]NO3), is called a basic salt. Since a salt may react with a solvent to yield different ions than were present in the salt (see hydrolysis), a solution of a normal salt may be acidic or basic; e.g., trisodium phosphate, Na3PO4, dissolves in and reacts with water to form a basic solution.
In addition to being classified as normal, acid, or basic, salts are categorized as simple salts, double salts, or complex salts. Simple salts, e.g., sodium chloride, contain only one kind of positive ion (other than the hydrogen ion in acid salts). Double salts contain two different positive ions, e.g., the mineral dolomite, or calcium magnesium carbonate, CaMg(CO3)2. Alums are a special kind of double salt. Complex salts, e.g., potassium ferricyanide, K3Fe(CN)6, contain a complex ion that does not dissociate in solution. A hydrate is a salt that includes water in its solid crystalline form; Glauber's salt and Epsom salts are hydrates.
Preparation of Salts
See M. Kurlansky, Salt: A World History (2002).
SALTAbbrev. for Southern African Large Telescope.
Salt(religion, spiritualism, and occult)
Much like iron, salt was believed to have supernatural origins and has become an essential part of most religious and magical rituals. The very word "salary" comes from the Latin salarium meaning "salt allowance," showing it to have great worth. The habitual use of salt is connected with the advance from nomadic to agricultural life. The gods were worshiped as the givers of the foods necessary for life; so salt, frequently together with bread, was associated with offerings to the deities. This was especially prevalent among the Greeks and Romans.
Since it is so essential to life—both human and animal—salt symbolically represents life. It is added to baptismal water, to water used in exorcism, and to the holy water used on a Wiccan altar. Some traditions of Witchcraft mark their Circle with salt. Magically, it is considered a great defense against evil. For this reason, people in the Middle Ages believed it to be a tool for preventing witchcraft and for destroying a witch. Even today, in the Ozarks, it is believed that if a woman complains that her food tastes too salty, she may well be a witch. There is an old saying in the region: "The Devil hates salt."
Since salt represents life, to spill salt is a bad omen for it presages spilling blood. In alchemy it represents the principle of body, the female, and earth. On the Wiccan and ceremonial altars it represents the element of earth. In the old British custom of "first-footing" (being the first person of the new year to set foot across another's doorstep), salt is one of the gifts presented by the first-footer to the homeowner.
Salt used to mark the line at the meal table between family or close friends and those who were casual visitors or menials. The former sat at the head of the table, while the latter sat "below the salt"—below where the salt cellar stood on the table.
Salt and incense were both religious and economic necessities of the ancient world. Via Lalaria, as one of the oldest roads in Italy, was used for moving the salt of Ostia to the Sabine country. Herodotus mentions the caravan route connecting the many oases of the Libyan desert as a road for the transportation of salt.
In Wiccan rituals, sea salt is the preferred type, although any regular salt is acceptable. There are various ways of processing sea salt, the traditional and possibly the oldest and purest method being by allowing the wind and sun alone to dry ocean brine that is channeled from the open sea into pristine shallow clay ponds. In this manner, Celtic Brittany farmers produce some of the finest and purest sea salt in the world.
a mountain range in northern Pakistan, between the valleys of the Indus and Jhelum rivers. The range stretches for a length of approximately 300 km, with elevations to 1,522 m (Mount Sakesar). The Salt Range constitutes a cuesta-like ledge below the southern edge of the Potwar Plateau. It is composed of crystalline rocks overlain with limestones and dolomites. There are large deposits of rock salt at Khewra and Nurpur and other sites. On the slopes there are separate pine, acacia, and olive groves.
the name of a class of chemical compounds that are crystalline under ordinary conditions and for which an ionic structure is typical. According to the theory of electrolytic dissociation, salts are chemical compounds that in solution dissociate into positively charged ions, or cations (mainly, of metals), and negatively charged ions, or anions. The various types of salts include normal, acid, basic, double, mixed, and complex salts. The most common laboratory method for the preparation of salts is the reactions of acids with bases, as well as reactions of acids with metals and, in many cases (depending on the electromotive forces series), reactions of salts themselves with metals.
A characteristic property of salts is solubility in polar solvents, especially water. In nature, accumulations of salts are formed mainly by sedimentation from aqueous solutions in inland sea basins (Aral Sea, Dead Sea) or in inlets almost cut off from the sea (Kara-Bogaz-Gol), as well as in closed mainland lakes (El’ton, Baskunchak).
Salts were known in antiquity. In addition to their traditional use in foods and medicine, salts came to be used industrially with the development of the chemical, glassmaking, leather, textile, and metallurgical industries. Some salts are used as mineral fertilizers.
REFERENCENekrasov, B. V. Osnovy obshchei khimii, vols. [1–2], 3rd ed. Moscow, 1973.
What does it mean when you dream about salt?
Used as seasoning in food, salt symbolizes flavor or piquancy. As one of the three primary elements of matter in alchemy representing—in contrast to mercury and sulfur—the principle of fixity and solidity, salt symbolizes someone who is steadfast and dependable, “the salt of the earth.”
SALT(1) See password salt.
(2) (Speech Application Language Tags) Extensions to HTML, XHTML and XML for voice recognition and synthesized speech and audio output. SALT is designed to support mixed modes including audio, video, text and graphics, depending on the device in the user's hands. For more information, visit the SALT Forum at www.saltforum.org.