Chemistry
Articles about matter, substances, reactions and chemical science.
Oxidizing agent
Oxygen
Oxygen (element O)
Oxygen (O, atomic number 8) is a reactive nonmetal essential for respiration, a major part of Earth's crust and atmosphere, and widely used in industry, medicine, and propulsion.
Oxygen difluoride
Oxygen difluoride (OF2)
Oxygen saturation
Oxygen saturation: dissolved oxygen in water and oxygenation in blood
Ozone
Palladium
Paraffin wax
Paris green
Patina
Pentaerythritol tetranitrate
Pentane
Pentane: properties, isomers, uses and safety
Pentene
Pentene (C5H10): isomers, properties and industrial uses
Pepper spray
Peptide bond
Peptide bond (amide linkage between amino acids)
Perbromate
Perbromate (BrO4−): properties, preparation and significance
Perbromic acid
Perchlorate
Perchlorate (ClO4−): chemistry, uses, health and environmental issues
Perchloric acid
Pericyclic reaction
Period (periodic table)
Period (periodic table row)
Period 1 element
Period 1 elements — hydrogen and helium
Period 2 element
Period 2 elements (lithium through neon)
Period 3 element
Period 4 element
Period 4 elements (fourth row of the periodic table)
Period 5 element
Period 6 element
Period 7 element
Periodate
Periodic acid
Periodic table
Periodic table (big)
Periodic table (metals and non-metals)
Permanganate
Permanganate (MnO4⁻): properties, reactions, uses and safety
Peroxide
Peroxide (O2 2−) — structure, types, uses and safety
Petrochemical
Petrochemical: Definition, Feedstocks, Processes and Uses
Petroleum coke
Petroleum coke (petcoke)
Petroleum product
Pewter
pH
pH: measure of acidity and alkalinity
Pharmaceutical chemistry
Pharmaceutical chemistry (medicinal chemistry): an overview
Phase change
Phase change (changes of state of matter)
Phenol
Phlogiston theory
Phlogiston theory: the historical chemical hypothesis of combustion
Phosgene
Phosgene (carbonyl chloride): properties, history and industrial uses
Phosgene oxime
Phosgene oxime (CX)
Phosphate
Phosphate: chemistry, biological role, types, and uses
Phosphide
Phosphide — chemistry, structure, reactions and applications
Phosphine
Phosphine (PH3) — properties, production, uses, and safety