On the Preparation of “Free Carbonic Acid”

Abstract

The [Co(PF3)4]0 anion can be precipitated from aqueous solutions with voluminous cations. During the conversion of HCo(PF3)d into [Co(PF3)4]0, a bathochroniic shift of the P-F valence vibrations is observed which is probably due to a reduction in the double-bond character of the P-F bond.At PF3-pressures above 200 atm and temperatures above 200 OC, tungsten hexachloride reacts with copper powder as halogen acceptor to form colorless crystals of hexakis(trifluorophosphine) tungsten(0). W(PF3)6 completes the series of hexakis(trifluorophosphine) complexes of the chromium group [4]. The new compound, m.p. 214'C, is completely analogous to the corresponding chromium and molybdenum complexes. It sublimes rapidly in a high vacuum at 4OoC and decomposes only above 32OoC with formation of a tungsten mirror. Its infrared spectrum has P-F valence vibrations at 914 (vs) and 852 (s) cm-1 [3] and indicates an octahedral structure of the diamagnetic complex. Received: December 3rd, 1964 [Z 876/704 IE] German version: Angew. Chem. 77, 132 (1965) [I] Trifluorophosphinemetal Complexes, Part VI. -Part V: Th. Kruck and A. Prasch, Angew. Chem. 76, 892 (1964); Angew. Chem. internat. Edit. 3, 754 (1964).[2] The preparation of Ni(PF3)4 from nickel iodide or metallic nickel will be described in a separate report.[3] Measured in the gas phase with a Perkin-Elmer Model 21 spectrophotometer with an NaCl prism; w = weak, s = strong, vs = very strong, sh = shoulder.

Trihydroxycarbeniumhexafluorometallate: Salze der protonierten Kohlensäure

“…[1] Das mit Orthoborsäure isoelektronische Trihydroxycarbenium-Ion C(OH) 3 1 lieû sich bisher nur in einem Substanzgemisch bei der Protonierung von Carbonaten oder Hydrogencarbonaten mit der Supersäure FSO 3 H/SbF 5 NMRspektroskopisch nachweisen. [2] Da Kohlensäure als Reaktant nicht zur Verfügung steht, [3,4] haben wir in Anlehnung an die Synthese von protoniertem Wasserstoffperoxid [5] Kohlensäure-bis(trimethylsilyl)ester [6] mit den Supersäuren HF/MF 5 (M As, Sb) gemäû Gleichung (1) umgesetzt.…”

“…Die meisten metallorganischen Dendrimere, über die bisher berichtet wurde, enthalten jedoch Metallionen entweder nur im Kern [2] oder an der Oberfläche; [3] metallorganische Dendrimere mit Übergangsmetallionen in jeder Generation sind bisher kaum untersucht worden. [4] Da solche metallorganischen Dendrimere durch aufeinanderfolgende metallorganische Reaktionen aufgebaut werden, ist diese Strategie wegen der niedrigen Stabilität der metallorganischen Komplexe nur sehr eingeschränkt nutzbar.…”

H2CO3→ CO2+ H2O decomposition in the presence of H2O, HCOOH, CH3COOH, H2SO4and HO2radical: instability of the gas-phase H2CO3molecule in the troposphere and lower stratosphere

“…This molecule was long believed to be an unstable and elusive species as it decomposes rapidly into CO 2 and H 2 O molecules. 1,34,35 Indeed, it was also believed in the past that the isolated H 2 CO 3 molecule cannot exist in a free state, and consequently, the existence of isolated H 2 CO 3 molecules in the gas-phase was controversial for a long time. 2 In 1987, Terlouw et al 1 rst detected free H 2 CO 3 molecule in the gas-phase from the thermolysis of the ammonium bicarbonate (NH 4 HCO 3 ) molecule via mass spectrometry, and hence, thereaer, the evidence for the possible existence of the H 2 CO 3 molecule in the gas-phase was established.…”

In Spite of the Chemist's Belief: Carbonic Acid Is Surprisingly Stable

“…Isolation of such an ether complex was achieved by the addition of an etheral solution of anhydrous hydrogen chloride to a suspension of finely crushed sodium bicarbonate in ether at 243 K. [9] Cooling the solution to 195 K resulted in the precipitation of a white crystalline etherate. In a similar procedure Gattow and Gerwath [10] used dimethyl ether and sodium carbonate at 238 K to prepare the dimethyl ether complex of carbonic acid. They obtained a solid which decomposed violently above 278 K, yielding water, carbon dioxide and ether.…”