FLUORIDES ARE ABSORBED FROM GI TRACT, LUNG, & SKIN. GI TRACT IS MAJOR SITE OF ABSORPTION. THE RELATIVELY SOL CMPD, SUCH AS SODIUM FLUORIDE, ARE ALMOST COMPLETELY ABSORBED. ... FLUORIDE HAS BEEN DETECTED IN ALL ORGANS & TISSUES, AND IT IS CONCENTRATED IN BONE, THYROID, AORTA, & PERHAPS KIDNEY. FLUORIDE IS PRIMARILY DEPOSITED IN BONE & TEETH, & THE DEGREE OF SKELETAL STORAGE IS RELATED TO INTAKE AND AGE. ... MAJOR ROUTE OF ... EXCRETION IS VIA THE KIDNEYS; ... /ALSO EXCRETED IN SMALL AMT/ IN SWEAT, MILK, AND INTESTINAL SECRETIONS. ... ABOUT 90% OF FLUORIDE ION FILTERED BY GLOMERULUS IS REABSORBED BY RENAL TUBULES. /FLUORIDE/
Solutions of fluoride salts are rapidly and almost completely absorbed from the gastrointestinal tract, probably by simple diffusion ... Less than 10% of the ingested fluoride is excreted in the feces, but the proportion varies with circumstances ... The simultaneous presence of strongly fluoride-binding ions, especially calcium ions, will reduce the absorption of fluoride ... In patients ingesting aluminum-containing antacids, fluoride absorption decr to about 40%, and the retention decr to nil. /Fluorides/
In the industrial environment, the respiratory tract is the major route of absorption of both gaseous and particulate fluoride. Hydrogen fluoride being highly soluble in water is rapidly taken up in the upper respiratory tract ... Depending on their aerodynamic characteristics, fluoride-containing particles will be deposited in the nasopharynx, the tracheo-bronchial tree and the alveoli ... Dermal absorption of fluoride has only been reported in the case of burns resulting from exposure to hydrofluoric acid ... . /Fluorides/
About 75% of the blood fluoride is present in the plasma; the rest is mainly in or on the red blood cells ... Fluoride in human serum exists in both ionic and nonionic forms. ... For the general population under steady-state conditions of exposure, the concn of fluoride ions in plasma is directly related to the fluoride content of the drinking water. /Fluorides/
Infrared spectroscopic and theoretical studies of the OTiF2, OZrF2 and OHfF2 molecules with terminal oxo ligands
作者:Yu Gong、Lester Andrews、Charles W. Bauschlicher、K. Sahan Thanthiriwatte、David A. Dixon
DOI:10.1039/c2dt31223a
日期:——
The isolated group 4 metal oxydifluoride molecules OMF2 (M = Ti, Zr, Hf) with terminal oxo groups are produced specifically on the spontaneous reactions of metal atoms with OF2 through annealing in solid argon. The product structures and vibrational spectra are characterized using matrix isolation infrared spectroscopy as well as B3LYP density functional and CCSD(T) frequency calculations. OTiF2 is
通过在固态氩气中退火,金属原子与OF 2的自发反应,产生了带有末端氧代基团的分离的第4组金属氧二氟化物分子OMF 2(M = Ti,Zr,Hf)。使用矩阵隔离红外光谱以及B3LYP密度泛函和CCSD(T)频率计算来表征产品结构和振动光谱。预测OTiF 2具有平面结构,而OZrF 2和OHfF 2都具有锥体结构,均具有单重态基态。每个产品分子观察到三种红外吸收,一种是M-O和两种M-F拉伸模式,并且相应分子进一步支持了这些分子的分配18 O班。第4组OMF 2分子的分子轨道显示出末端氧代基团的三键特征,这也得到NBO分析的支持。这些分子轨道包括一个σ键(O 2p + Ti sd杂化物),一个正常的电子对π键(O 2p + Ti d)和一个由向重叠的Ti d轨道供以O孤对而产生的和格π键。OMF 2的M–O键解离能与双原子氧化物分子中的相当。还通过两种稍低频率的键拉伸模式观察到了OTiF中间体,并且在互补TiO
Concerning the mechanism of formation of oxygen difluoride
作者:Evan H. Appelman、Albert W. Jache
DOI:10.1021/ja00240a026
日期:1987.3
Passage of F/sub 2/ over ice at temperatures around -50 /sup 0/C produces a mixture of O/sub 2/, HOF, and OF/sub 2/, along with small amounts of H/sub 2/O/sub 2/. The involvement of HOF in the formation of OF/sub 2/ has been demonstrated through the use of HOF labeled both with /sup 18/O and with radioactive /sup 18/O and with radioactive /sup 18/F. The reaction that produces the OF/sub 2/ has been
1927). In the preparationof fluorine by the electrolysis of the acid potassium fluoride, it was noticed that at the commencement of the operation, owing to the presence in the liquid of a small quantity of water, a new gas was obtained of which the formula has been established as F2O, probably a monoxide of fluorine. In my view the new gas is not a monoxide of fluorine, F2O, but a difluoride of oxygen
作者:William W. Wilson、Richard D. Wilson、Karl O. Christe
DOI:10.1016/0022-1902(81)80335-1
日期:1981.1
A new method for the synthesis of NF4+ salts is reported. It permits the synthesis of otherwise inaccessible salts derived from nonvolatile Lewis acids which do not possess HF-soluble cesium salts. The method was successfully applied to the synthesis of the novel salt NF4+UF5O−. This compound is a yellow solid, stable at room temperature. It was characterized by analysis and vibrational spectroscopy