Four schedules

The Convention has four Schedules of controlled substances, ranging from Schedule I (most restrictive) to Schedule IV (least restrictive). A list of psychotropic substances, and their corresponding Schedules, was annexed to the 1971 treaty. The text of the Convention does not contain a formal description of the features of the substances fitting in each Schedule, in contrast to the US Controlled Substances Act of 1970, which gave specific criteria for each Schedule in the US system. The amphetamine-type stimulants (ATS), a legal class of stimulants – not all of which are substituted amphetamines – were defined in the 1971 treaty and in subsequent revisions.[10] A 2002 European Parliament report and a 1996 UNODC report on ATS describe the international Schedules as listed below.[10][11]

  • Schedule I includes drugs claimed to create a serious risk to public health, whose therapeutic value is not currently acknowledged by the Commission on Narcotic Drugs. It includes synthetic psychedelics such as LSD in addition to natural psychedelics like certain substituted tryptamines. ATS such as cathinoneMDA, and MDMA (ecstasy) also fall under this category.[10]

  • Schedule II includes certain ATS with therapeutic uses, such as amphetamine and methylphenidate,[10] as well as some analgesics such as morphine.

  • Schedule III includes barbiturate products with fast or average effects, which have been the object of serious abuse even though useful therapeutically, strongly sedative benzodiazepines like flunitrazepam and some analgesics like buprenorphine. The only ATS in this category is cathine.[10] Dronabinol, which is a THC isomer, is also included.

  • Schedule IV includes some weaker barbiturates like (phenobarbital) and other hypnotics, hypnoticanxiolytic benzodiazepines (except flunitrazepam), and some weaker stimulants. It has been suggested that THC be moved to this category but it is still listed as schedule I. Over a dozen ATS are included in this category, including the substituted amphetamine phentermine.[10]

The Commission on Narcotic Drugs and the World Health Organizationwere empowered to add, remove, and transfer drugs among the treaty's four schedules of controlled substances


There are four basic types of bonds that can be formed between two or more (otherwise non-associated) molecules, ions or atoms. Intermolecular forcescause molecules to be attracted or repulsed by each other. Often, these define some of the physical characteristics (such as the melting point) of a substance.

  • A large difference in electronegativity between two bonded atoms will cause a permanent charge separation, or dipole, in a molecule or ion. Two or more molecules or ions with permanent dipoles can interact within dipole-dipole interactions. The bonding electrons in a molecule or ion will, on average, be closer to the more electronegative atom more frequently than the less electronegative one, giving rise to partial charges on each atom, and causing electrostatic forces between molecules or ions.

  • hydrogen bond is effectively a strong example of an interaction between two permanent dipoles. The large difference in electronegativities between hydrogen and any of fluorinenitrogen and oxygen, coupled with their lone pairs of electrons cause strong electrostatic forces between molecules. Hydrogen bonds are responsible for the high boiling points of water and ammonia with respect to their heavier analogues.

  • The London dispersion force arises due to instantaneous dipoles in neighbouring atoms. As the negative charge of the electron is not uniform around the whole atom, there is always a charge imbalance. This small charge will induce a corresponding dipole in a nearby molecule; causing an attraction between the two. The electron then moves to another part of the electron cloud and the attraction is broken.

  • cation–pi interaction occurs between a pi bond and a cation.


Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Four elements constitute the composition of soil