37 articles
Alkalinity
Alkalinity, also called total alkalinity, is the capacity of water to neutralize acid, arising mostly from bicarbonate and carbonate ions and measured by titration with acid.
Bicarbonate
Bicarbonate (hydrogencarbonate), the ion HCO3−, is the conjugate base of carbonic acid and the main buffer of blood pH; its sodium salt is baking soda.
Carbon dioxide
Carbon dioxide (CO₂), also called carbonic acid gas, is a colorless, odorless greenhouse gas produced by respiration and combustion, with a solid form known as dry ice.
Carbon dioxide carboxylation
Carbon dioxide carboxylation is a family of catalytic reactions using CO₂ as the C1 source to convert organohalides, alkenes, and C–H bonds into carboxylic acids.
Carbon dioxide cycloaddition
Carbon dioxide cycloaddition is the catalytic coupling of CO2 with epoxides to form cyclic carbonates, a non-redox, 100% atom-economical CO2 fixation reaction already performed industrially.
Carbon dioxide hydrogenation
Carbon dioxide hydrogenation is the catalytic reaction of CO2 with hydrogen to make reduced carbon products, chiefly methanol, carbon monoxide via the reverse water–gas shift reaction, methane, and formic acid.
Carbon dioxide in Earth's atmosphere
Carbon dioxide in Earth's atmosphere is the trace gas CO2 that chiefly controls Earth's greenhouse effect; in 2025 it reached 425.6 ppm, 53 percent above preindustrial levels.
Carbonate
Carbonate is a polyatomic anion with the formula CO3²⁻, a carbon atom surrounded by three oxygen atoms and carrying a −2 charge; the term also covers its salts and minerals.
Carbonic acid
Carbonic acid (H₂CO₃), also called aerial acid, is a weak acid formed when carbon dioxide dissolves in water; it regulates the pH of oceans and of blood.
Carboxylation
Carboxylation is a chemical reaction that adds a carboxyl group to an organic compound, typically using carbon dioxide, yielding a carboxylic acid such as salicylic acid.
CO2 hydration
CO2 hydration: CO2 + H2O forming bicarbonate and a proton, also called carbonic anhydrase catalysis. Spontaneously slow; carbonic anhydrases accelerate it up to a million fold, and cyanobacteria couple it to NDH-1 electron transport via ChpX and ChpY.
CO2 hydrosilylation
CO2 hydrosilylation is the catalytic reduction of carbon dioxide with hydrosilanes, studied since 1981, that converts CO2 through formate, formaldehyde, and methanol levels using strong Si–O bond formation as the driving force.
CO2-expanded liquids
CO2-expanded liquids (CXLs) are organic liquids into which compressed carbon dioxide is dissolved under pressure, tuning properties like solvent strength and viscosity for use in catalysis and separations.
Dry ice
Dry ice, also sold as Cardice, is the solid form of carbon dioxide, used as a refrigerant because it sublimes directly to gas at −78.5 °C, leaving no liquid residue.
Electrocarboxylation
Electrocarboxylation, also called electrochemical carboxylation, is an organic electrosynthesis method that electrochemically fixes carbon dioxide into organic substrates at a cathode, forming carbon–carbon bonds and yielding carboxylic acids.
Electrochemical carboxylation
Electrochemical carboxylation, also called electrocarboxylation, uses electrochemical reducing power, typically at a cathode, to install carbon dioxide as a carboxyl group onto organic substrates, giving carboxylic acids under mild conditions.
Electrochemical reduction of carbon dioxide
Electrochemical reduction of carbon dioxide, or carbon dioxide electrolysis, is an electrolysis process that converts CO2 into products such as carbon monoxide, formic acid, and ethylene.
Formate pathway in CO2 hydrogenation
The formate pathway in CO2 hydrogenation is a reaction mechanism in which CO2 is hydrogenated via a formate intermediate to methanol, avoiding the CO route, on Cu/ZnO catalysts.
Frustrated Lewis pair CO2 activation
Frustrated Lewis pair CO2 activation is the capture and distortion of carbon dioxide by a sterically hindered Lewis acid and base that cannot form a classical adduct.
Iron porphyrin electrocatalytic CO2 reduction
Iron porphyrin electrocatalytic CO2 reduction is the conversion of carbon dioxide to carbon monoxide catalyzed by iron tetraphenylporphyrin derivatives; a landmark 2012 Science report achieved 50 million turnovers.
Liquid carbon dioxide
Liquid carbon dioxide, or liquid CO2, is carbon dioxide held liquid by pressure between −56.6 and 31.0 °C, used in food freezing, fire suppression, cleaning, and refrigeration.
Lithium carbonate
Lithium carbonate (Li2CO3) is the lithium salt of carbonic acid, a white powder that is the main commercial form of lithium and the mood-stabilizing drug for bipolar I disorder.
Metal carbon dioxide complex
A metal carbon dioxide complex is a coordination complex where a CO2 molecule binds a metal center as a ligand, activating it for reduction and other reactions.
Methanation
Methanation is the catalytic hydrogenation of carbon oxides (CO and CO₂) to methane and water, used to purify synthesis gas and make substitute natural gas.
Molecular structure and bonding of carbon dioxide
Carbon dioxide is a linear triatomic molecule, O=C=O, with two equal C=O double bonds of 116 pm, D∞h symmetry, zero dipole moment, and three vibrational fundamentals.
Nickel-catalyzed carboxylation with CO2
Nickel-catalyzed carboxylation with CO2 is a family of reactions using nickel catalysts and carbon dioxide to convert organic halides, alkenes, and C–H bonds into carboxylic acids.
Nonthermal plasma CO2 conversion
Nonthermal plasma CO2 conversion is a chemical process in which energetic electrons split stable CO2 into carbon monoxide and oxygen without heating the bulk gas.
PCO2
PCO2, or PaCO2, is the partial pressure of carbon dioxide dissolved in arterial or venous blood, normally 35 to 45 mmHg, and a marker of alveolar ventilation.
Photocatalytic CO2 reduction by cobalt polypyridyl complexes
Photocatalytic CO2 reduction by cobalt polypyridyl complexes is light-driven chemistry in which a cobalt catalyst with polypyridine ligands, a photosensitizer, and a sacrificial donor convert carbon dioxide into carbon monoxide or formate.
Photoredox-catalyzed carboxylation with CO2
Photoredox-catalyzed carboxylation with CO2 is a family of organic reactions in which a visible-light photocatalyst activates carbon dioxide to form carbon–carbon bonds under mild conditions.