منابع مشابه
Tunnelling in carbonic acid.
The cis,trans-conformer of carbonic acid (H2CO3), generated by near-infrared radiation, undergoes an unreported quantum mechanical tunnelling rotamerization with half-lives in cryogenic matrices of 4-20 h, depending on temperature and host material. First-principles quantum chemistry at high levels of theory gives a tunnelling half-life of about 1 h, quite near those measured for the fastest ro...
متن کاملAqueous carbonic acid (H2CO3).
Carbonic acid (H2CO3) is a molecule right at the interface between organic and inorganic chemistry. In fact, according to some definitions it is an organic molecule, while according to others it is an inorganic molecule. Its exceptionality can also be recognized from the fact that it formally belongs neither to the mononor dicarboxylic acids, even though it is a C1 diprotic acid. The diprotic n...
متن کاملCarbonic Acid and Bicarbonate in Urine
In the course of some studies of acid excretion undertakenin this laboratory it became desirable to learn something if possible, of the factors which determine the elimination of carbonic acid in urine. Although carbonic acid may be regarded as only incidentally a urinary acid, the bulk of its production leaving the body by way of the lungs, it is, nevertheless, regularly present in urine, both...
متن کاملCalcium, carbonic anhydrase and gastric acid secretion.
Previous data concerning the action of calcium (Ca) on gastric acid secretion (GAS) indicated that calcium ions increase GAS elicited by gastrin released through a vagal mechanism, and also by a direct effect on parietal cells. Our research showed that the stimulating effect of calcium on gastric acid secretion can be antagonized by verapamil administration, which reduces gastric acid secretion...
متن کاملDensity functional study of carbonic acid clusters
Density functional calculations on carbonic acid H2CO3 are extended to clusters of up to five such units. The most stable forms are the linear, hydrogen-bonded analogs of the dimer with anti–anti orientation. We calculate structures and vibration frequencies, as well as the energy required to bend and stretch the linear isomers. Linear chains of up to ;20 units should be favored over ring struc...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Science
سال: 1899
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.9.221.459