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59-432: The Caroní is one of the rivers with the highest discharge rates in the world, with respect to the area of its basin. The average discharge is 4,850 cubic metres per second (171,000 cu ft/s), with variations caused by the wet/dry seasons. The average maximum discharge is 6,260 cubic metres per second (221,000 cu ft/s), and the average minimum is 3,570 cubic metres per second (126,000 cu ft/s). Among

118-526: A hydrothermal reaction . The resulting mixture can increase the content of dissolved organic matter (DOM) and total organic carbon (TOC) in soil. Lignite (brown coal) may also be oxidized to produce humic substances, reversing the natural process of coal formation under anoxic and reducing conditions . This form of "mineral-derived fulvic acid" is widely used in China. This process also occurs in nature, producing leonardite . In economic geology ,

177-513: A pK 1 value around 4 for protonation of carboxyl groups and around 8 for protonation of phenolate groups in HA. Fulvic acids are more acidic than HA. There is considerable overall similarity among individual humic acids. For this reason, measured pK values for a given sample are average values relating to the constituent species. The other important characteristic is charge density . The more recent determinations of molecular weights of HS show that

236-677: A by-product from the sulfite pulping of wood, are valorized in the industrial fabrication of concrete where they serve as water reducer , or concrete superplasticizer , to decrease the water-cement ratio (w/c) of fresh concrete while preserving its workability. The w/c ratio of concrete is one of the main parameter controlling the mechanical strength of hardened concrete and its durability. The same wood pulping process can also be applied to obtain humus-like substances by hydrolysis and oxidation . A kind of artificial "lignohumate" can be directly produced from wood in this way. Agricultural litter can be turned into an artificial humic substance by

295-423: A proliferation of conflicting definitions. This lack of consensus makes it difficult to communicate scientific understanding of soil processes and properties accurately." The presence of humic acid in water intended for potable or industrial use can have a significant impact on the treatability of that water and the success of chemical disinfection processes. For instance, humic and fulvic acids can react with

354-474: A regulative force must exist within living bodies. Berzelius also contended that compounds could be distinguished by whether they required any organisms in their synthesis (organic compounds) or whether they did not ( inorganic compounds ). Vitalism taught that formation of these "organic" compounds were fundamentally different from the "inorganic" compounds that could be obtained from the elements by chemical manipulations in laboratories. Vitalism survived for

413-452: A short period after the formulation of modern ideas about the atomic theory and chemical elements . It first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid , a compound known to occur only in living organisms, from cyanogen . A further experiment was Wöhler's 1828 synthesis of urea from the inorganic salts potassium cyanate and ammonium sulfate . Urea had long been considered an "organic" compound, as it

472-917: A single acid ; rather, it is a complex mixture of many different acids containing carboxyl and phenolate groups so that the mixture behaves functionally as a dibasic acid or, occasionally, as a tribasic acid . Commercial humic acid used to amend soil is manufactured using these same well established procedures. Humic acids can form complexes with ions that are commonly found in the environment creating humic colloids . A sequential chemical fractionation called Humeomics can be used to isolate more homogeneous humic fractions and determine their molecular structures by advanced spectroscopic and chromatographic methods. Substances identified in humic extracts and directly in soil include mono-, di-, and tri- hydroxycarboxylic acids , fatty acids , dicarboxylic acids , linear alcohols, phenolic acids , terpenoids , carbohydrates, and amino acids. This suggests humic molecules may form

531-404: A single element and so not generally considered chemical compounds . The word "organic" in this context does not mean "natural". Vitalism was a widespread conception that substances found in organic nature are formed from the chemical elements by the action of a "vital force" or "life-force" ( vis vitalis ) that only living organisms possess. In the 1810s, Jöns Jacob Berzelius argued that

590-634: A small percentage of Earth's crust , they are of central importance because all known life is based on organic compounds. Living things incorporate inorganic carbon compounds into organic compounds through a network of processes ( the carbon cycle ) that begins with the conversion of carbon dioxide and a hydrogen source like water into simple sugars and other organic molecules by autotrophic organisms using light ( photosynthesis ) or other sources of energy. Most synthetically-produced organic compounds are ultimately derived from petrochemicals consisting mainly of hydrocarbons , which are themselves formed from

649-504: A solution of potassium hydroxide and, after subsequent addition of an acid, obtained an amorphous dark precipitate (i.e., humic acid). Aquatic humic substances were isolated for the first time in 1806, from spring water by Jöns Jakob Berzelius . In terms of chemistry, FA, HA, and humin share more similarities than differences and represent a continuum of humic molecules. All of them are constructed from similar aromatic , polyaromatic , aliphatic , and carbohydrate units and contain

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708-430: A supramolecular structures held together by non-covalent forces, such as van der Waals force , π-π , and CH-π bonds. Since the dawn of modern chemistry, humic substances are among the most studied among natural materials. Despite long study, their molecular structure remains debatable The traditional view has been that humic substances are hetero- poly-condensates, in varying associations with clay. A more recent view

767-421: A transition metal and to oxygen, and are often prepared directly from metal and carbon monoxide . Nickel tetracarbonyl is typically classified as an organometallic compound as it satisfies the broad definition that organometallic chemistry covers all compounds that contain at least one carbon to metal covalent bond; it is unknown whether organometallic compounds form a subset of organic compounds. For example,

826-1692: A variety of ways. One major distinction is between natural and synthetic compounds. Organic compounds can also be classified or subdivided by the presence of heteroatoms , e.g., organometallic compounds , which feature bonds between carbon and a metal , and organophosphorus compounds , which feature bonds between carbon and a phosphorus . Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers . Natural compounds refer to those that are produced by plants or animals. Many of these are still extracted from natural sources because they would be more expensive to produce artificially. Examples include most sugars , some alkaloids and terpenoids , certain nutrients such as vitamin B 12 , and, in general, those natural products with large or stereoisometrically complicated molecules present in reasonable concentrations in living organisms. Further compounds of prime importance in biochemistry are antigens , carbohydrates , enzymes , hormones , lipids and fatty acids , neurotransmitters , nucleic acids , proteins , peptides and amino acids , lectins , vitamins , and fats and oils . Compounds that are prepared by reaction of other compounds are known as " synthetic ". They may be either compounds that are already found in plants/animals or those artificial compounds that do not occur naturally . Most polymers (a category that includes all plastics and rubbers ) are organic synthetic or semi-synthetic compounds. Many organic compounds—two examples are ethanol and insulin —are manufactured industrially using organisms such as bacteria and yeast. Typically,

885-428: Is an important aspect of the biological role of humic acids in regulating bioavailability of metal ions. Criticism Decomposition products of dead plant materials form intimate associations with minerals, making it difficult to isolate and characterize soil organic constituents. 18th century soil chemists successfully used alkaline extraction to isolate a portion of the organic constituents in soil. This led to

944-972: Is any compound that contains a significant amount of carbon—even though many of the organic compounds known today have no connection to any substance found in living organisms. The term carbogenic has been proposed by E. J. Corey as a modern alternative to organic , but this neologism remains relatively obscure. The organic compound L -isoleucine molecule presents some features typical of organic compounds: carbon–carbon bonds , carbon–hydrogen bonds , as well as covalent bonds from carbon to oxygen and to nitrogen. As described in detail below, any definition of organic compound that uses simple, broadly-applicable criteria turns out to be unsatisfactory, to varying degrees. The modern, commonly accepted definition of organic compound essentially amounts to any carbon-containing compound, excluding several classes of substances traditionally considered "inorganic". The list of substances so excluded varies from author to author. Still, it

1003-986: Is cumbersome to measure their exact concentrations in the humic superstructure. For this reason, concentrations of humic acid are traditionally estimated out of concentrations of organic matter, typically from concentrations of total organic carbon (TOC) or dissolved organic carbon (DOC). Extraction procedures are bound to alter some of the chemical linkages present in the soil humic substances (mainly ester bonds in biopolyesters such as cutins and suberins). The humic extracts are composed of large numbers of different bio-organic molecules that have not yet been totally separated and identified. However, single classes of residual biomolecules have been identified by selective extractions and chemical fractionation, and are represented by alkanoic and hydroxy alkanoic acids, resins, waxes, lignin residues, sugars, and peptides. Organic matter soil amendments have been known by farmers to be beneficial to plant growth for longer than recorded history. However,

1062-710: Is generally agreed upon that there are (at least) a few carbon-containing compounds that should not be considered organic. For instance, almost all authorities would require the exclusion of alloys that contain carbon, including steel (which contains cementite , Fe 3 C ), as well as other metal and semimetal carbides (including "ionic" carbides, e.g, Al 4 C 3 and CaC 2 and "covalent" carbides, e.g. B 4 C and SiC , and graphite intercalation compounds, e.g. KC 8 ). Other compounds and materials that are considered 'inorganic' by most authorities include: metal carbonates , simple oxides of carbon ( CO , CO 2 , and arguably, C 3 O 2 ),

1121-427: Is in the thousands  The average composition of HA and FA can be represented by model structures. The presence of carboxylate and phenolate groups gives the humic acids the ability to form complexes with ions such as Mg , Ca , Fe , and Fe creating humic colloids .. Many humic acids have two or more of these groups arranged so as to enable the formation of chelate complexes. The formation of (chelate) complexes

1180-479: Is on a carbon atom. For historical reasons discussed below, a few types of carbon-containing compounds, such as carbides , carbonates (excluding carbonate esters ), simple oxides of carbon (for example, CO and CO 2 ) and cyanides are generally considered inorganic compounds . Different forms ( allotropes ) of pure carbon, such as diamond , graphite , fullerenes and carbon nanotubes are also excluded because they are simple substances composed of

1239-412: Is soluble in water at neutral and alkaline pH, but insoluble at acidic pH < 2. Fulvic acid (FA) is soluble in water at any pH. Humin is not soluble in water at any pH. This definition of humic substances is largely operational. It is rooted in the history of soil science and, more precisely, in the tradition of alkaline extraction, which dates back to 1786, when Franz Karl Achard treated peat with

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1298-446: Is that relatively small molecules also play major a role. A typical humic substance is a mixture of many molecules, some of which are based on a motif of aromatic nuclei with phenolic and carboxylic substituents, linked together;  The functional groups that contribute most to surface charge and reactivity of humic substances are phenolic and carboxylic groups. Humic substances commonly behave as mixtures of dibasic acids, with

1357-404: Is the large molecular complexity of the soil humeome that confers to humic matter its bioactivity in, its stabilty in ecosystems ,soil and its role as plant growth promoter (in particular plant roots). The academic definition of humic substances is under debate and some researchers argue against the traditional concepts of humification and seek to forgo alkali extract method and directly analyze

1416-500: Is the result of a alkaline extraction from solid sources of NOM the adsorption of HS on a resin. A newer view of humic substances is that they are not mostly high-molecular-weight macropolymers but rather represent a heterogeneous mixture of relatively small molecular components of the soil organic matter auto-assembled in supramolecular associations and are composed of a variety of compounds of biological origin and synthesized by abiotic and biotic reactions in soil. and surface waters It

1475-401: Is treated on a resin column to separate fulvic acid components from other acid soluble compounds. The fraction of NOM not extracted by 0.1 NaOH is humin. Humic acid plus fulvic acid is extracted from natural waters using a resin column after microfiltration and acidification to pH 2. The humic materials are eluted from the column with NaOH, and humic acid is precipitated at pH 1. After adjusting

1534-699: The Negro River , or Rio Negro in Brazil, Venezuela and Colombia. In the late 1940s diamonds were found in the Caroní basin near the famous Lost World Region which then was accessible only by aircraft and four wheel drive vehicles. The river drain the Guayanan Highlands moist forests ecoregion. The Caroní basin covers 95,000 square kilometres (37,000 sq mi) and is part of the Orinoco basin,

1593-781: The allotropes of carbon, cyanide derivatives not containing an organic residue (e.g., KCN , (CN) 2 , BrCN , cyanate anion OCN , etc.), and heavier analogs thereof (e.g., cyaphide anion CP , CSe 2 , COS ; although carbon disulfide CS 2 is often classed as an organic solvent). Halides of carbon without hydrogen (e.g., CF 4 and CClF 3 ), phosgene ( COCl 2 ), carboranes , metal carbonyls (e.g., nickel tetracarbonyl ), mellitic anhydride ( C 12 O 9 ), and other exotic oxocarbons are also considered inorganic by some authorities. Nickel tetracarbonyl ( Ni(CO) 4 ) and other metal carbonyls are often volatile liquids, like many organic compounds, yet they contain only carbon bonded to

1652-530: The Caroni ideally suited for the generation of hydroelectric energy with four plants along its course ( Macagua I, II and III ), near its mouth, the Caruachi , some 30 kilometres (19 mi) aback, and lastly the plant of Guri , in the middle of Necoima or Necuima, some 80 kilometres (50 mi) from Puerto Ordaz. This plant has its reservoir, with an area of 4,000 square kilometres (1,500 sq mi), in

1711-578: The Caroní river, its fauna and inhabitants living along its shore. High levels of mercury have been found not only in the Caroní river but also in Lake Guri and further downstream. The government of Venezuela pledged to reduce illegal mining activities with the sustainable development plan for mining from 2016-18. Illegal mining surged under the government of Hugo Chávez , due to the nationalization of mines run by international mining companies and this had

1770-569: The Latin word humus , meaning "soil, earth". Humic substances represent the major part of organic matter in soil , peat , coal , and sediments , and are important components of dissolved natural organic matter (NOM) in lakes (especially dystrophic lakes ), rivers, and sea water . Humic substances account for 50 – 90% of cation exchange capacity in soils. "Humic substances" is an umbrella term covering humic acid, fulvic acid and humin, which differ in solubility. By definition, humic acid (HA)

1829-572: The North Carolina State University College of Agriculture and Life Sciences showed that addition of humate to soil significantly increased root mass in creeping bentgrass turf. A 2018 study by scientists at the University of Alberta showed that humic acids can reduce prion infectivity in laboratory experiments, but that this effect may be uncertain in the environment due to minerals in the soil that buffer

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1888-446: The chemicals used in the chlorination process to form disinfection byproducts such as dihaloacetonitriles, which are toxic to humans. Accurate methods of establishing humic acid concentrations are therefore essential in maintaining water supplies, especially from upland peaty catchments in temperate climates. As a lot of different bio-organic molecules in very diverse physical associations are mixed together in natural environments, it

1947-417: The chemistry and function of the organic matter have been a subject of controversy since humans began postulating about it in the 18th century. Until the time of Liebig , it was supposed that humus was used directly by plants, but, after Liebig showed that plant growth depends upon inorganic compounds, many soil scientists held the view that organic matter was useful for fertility only as it was broken down with

2006-548: The confluence with the Icabarú River and San Salvador de Paúl, there are several artisanal gold mines, mainly on the left hand side of the river outside the national park, but a few can also be found on the right hand side inside the Canaima National Park . Besides the devastating effects of logging and deforestation to clear the site for the mines, the far greater danger is the use of mercury which poisons

2065-417: The definition of humic substances like humic and fulvic acids relies on their separation through these methods, it raises the question of whether the distinction between these compounds accurately reflects the natural state of organic matter in soil. Despite these concerns, the 'humification' theory persists in the field and in even textbooks, and attempts to redefine 'humic substances' in soil have resulted in

2124-437: The effect. Humans can affect the production of humic substances via a variety of ways: by making use of natural processes by composting lignin or adding biochar (see soil rehabilitation ), or by industrial synthesis of artificial humic substances from organic feedstocks directly. These artificial substances may be similarly divided into artificial humic acid (A-HA) and artificial fulvic acid (A-FA). Lignosulfonates ,

2183-938: The evidence of covalent Fe-C bonding in cementite , a major component of steel, places it within this broad definition of organometallic, yet steel and other carbon-containing alloys are seldom regarded as organic compounds. Thus, it is unclear whether the definition of organometallic should be narrowed, whether these considerations imply that organometallic compounds are not necessarily organic, or both. Metal complexes with organic ligands but no carbon-metal bonds (e.g., (CH 3 CO 2 ) 2 Cu ) are not considered organometallic; instead, they are called metal-organic compounds (and might be considered organic). The relatively narrow definition of organic compounds as those containing C-H bonds excludes compounds that are (historically and practically) considered organic. Neither urea CO(NH 2 ) 2 nor oxalic acid (COOH) 2 are organic by this definition, yet they were two key compounds in

2242-407: The extracts into HA and FA. The International Humic Substances Society advocates the use of standard laboratory methods for preparation of humic and fulvic acids. Humic substances are extracted from soil and other solid sources using 0.1 M NaOH, under and a nitrogen atmosphere, to prevent abiotic oxidation of some of the components of HS. The HA is then precipitated at pH 1, and the soluble fraction

2301-404: The high pressure and temperature degradation of organic matter underground over geological timescales. This ultimate derivation notwithstanding, organic compounds are no longer defined as compounds originating in living things, as they were historically. In chemical nomenclature, an organyl group , frequently represented by the letter R, refers to any monovalent substituent whose open valence

2360-457: The highest free fall of the world, almost 1,000 metres (3,300 ft), and Kukenan Falls, the tenth on the world scale with a 610-metre (2,000 ft) free fall. Others falls with less height but high volume are the Aponwao, Caruay and La Llovizna waterfalls. Because of its high discharge rate, with a yearly average of 4,850 cubic metres per second (171,000 cu ft/s) and a steep slope,

2419-410: The historic extremes are 17,576 cubic metres per second (620,700 cu ft/s). The Caroní supplies 15.5 percent of the discharge of the Orinoco river. One of the characteristics of the Caroní's water is the dark color, caused by the high amount of humic acids due to the incomplete decomposition of the phenol content of the vegetation. The Caroní thus belongs to the blackwater rivers, as does

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2478-421: The idea that plants may be able to absorb the soluble forms of humus; this may in fact be an essential process for the uptake of otherwise insoluble iron oxides. A study on the effects of humic acid on plant growth was conducted at Ohio State University which said in part "humic acids increased plant growth" and that there were "relatively large responses at low application rates". A 1998 study by scientists at

2537-448: The lab are resistant to further biodegradation. Their structure, elemental composition and content of functional groups of a given sample depend on the water or soil source and on the specific procedures and conditions of extraction. Nevertheless, the average properties of lab extractes HS from different sources are remarkably similar. Historically, scientists have used variations of similar methods for extracting HS from NOM and separation

2596-715: The middle of the river, and has a power of 10,000 MW, and is now the third biggest in the world, after the Three Gorges dam in China (22,500 MW) and the Itaipu Dam in Paraguay and Brazil (14,000 MW) In the high basin of the rivers that form the Caroni (Aponguao, Cuquenán and Yuruaní) the Gran Sabana is spread out, partly belonging to the Canaima National Park . Along the Caroní River between

2655-601: The mineral mellite ( Al 2 C 6 (COO) 6 ·16H 2 O ). A slightly broader definition of the organic compound includes all compounds bearing C-H or C-C bonds. This would still exclude urea. Moreover, this definition still leads to somewhat arbitrary divisions in sets of carbon-halogen compounds. For example, CF 4 and CCl 4 would be considered by this rule to be "inorganic", whereas CHF 3 , CHCl 3 , and C 2 Cl 6 would be organic, though these compounds share many physical and chemical properties. Organic compounds may be classified in

2714-547: The molecular weights are not as great as once thought.  Reported  number average molecular weights of soil HA are < 6000 but they are highly poly disperse with some components with much larger measure molecular weights and much lower.  Measured number average molecular weights of aquatic HS with HA <= 1700 and FA< 900.  The aquatic HA and FA are also highly poly disperse.  The number of individually distinct components in HS, as measured by mass spectroscopy

2773-515: The most important river of Venezuela. This means for the two big rivers that they have very similar hydrographic characteristics. The Caroní itself and its tributary the Paragua are rivers with a staircase , in the sense that many falls and rapids are alternated with stretches with gentle slopes, with many meanders and oxbow lakes (naturally cut off meanders). Among the most important falls of these rivers and their tributaries are Angel Falls , with

2832-1092: The nanoparticles can then be captured using a magnet. Archeology finds that ancient Egypt used mudbricks reinforced with straw and humic acids. Organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond ; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-containing compounds such as alkanes (e.g. methane CH 4 ) and its derivatives are universally considered organic, but many others are sometimes considered inorganic , such as halides of carbon without carbon-hydrogen and carbon-carbon bonds (e.g. carbon tetrachloride CCl 4 ), and certain compounds of carbon with nitrogen and oxygen (e.g. cyanide ion CN , hydrogen cyanide HCN , chloroformic acid ClCO 2 H , carbon dioxide CO 2 , and carbonate ion CO 2− 3 ). Due to carbon's ability to catenate (form chains with other carbon atoms ), millions of organic compounds are known. The study of

2891-602: The negative consequence of an increase of mercury use as other processes are more difficult and costly to use for illegal, artisanal mining . 8°20′43″N 62°43′09″W  /  8.34528°N 62.71917°W  / 8.34528; -62.71917 Humic acid Humic substances ( HS ) are colored relatively recalcitrant organic compounds naturally formed during long-term decomposition and transformation of biomass residues. The color of humic substances varies from bright yellow to light or dark brown leading to black. The term comes from humus , which in turn comes from

2950-722: The pH to 2 fulvic acid is separated from other acid soluble compounds, using a resin column as with solid phase sources. An analytical method for quantifying humic acid and fulvic acid in commercial ores and humic products, has been developed based on the IHSS humic acid and fulvic acid preparation methods. Scientists associated with the IHSS have also isolated the entire NOM from black water streams using reverse osmosis  The retentate from this process contains both humic and fulvic acids, predominately humic acid. The NOM from hard water streams has been isolated using  reverse osmosis and electrodialysis in tandem. Extracted humic acid not

3009-647: The properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry . For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts ), along with a few other exceptions (e.g., carbon dioxide , and even hydrogen cyanide despite the fact it contains a carbon-hydrogen bond), are generally considered inorganic . Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only

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3068-405: The release of its constituent nutrient elements into inorganic forms. At the present time, soil scientists hold a more holistic view and at least recognize that humus influences soil fertility through its effect on the water-holding capacity of the soil. Also, since plants have been shown to absorb and translocate the complex organic molecules of systemic insecticides, they can no longer discredit

3127-571: The same functional groups (mainly carboxylic , phenolic , and ester groups), albeit in varying proportions. Water solubility of humic substances is primarily governed by interplay of two factors: the amount of ionizable functional groups and (mainly carboxylic) and molecular weight (MW). In general, fulvic acid has a higher amount of carboxylic groups and lower average molecular weight than does humic acid. Measured average molecular weights vary with source, however, molecular weight distributions of HA and FA significantly overlap. Age and origin of

3186-491: The soil, The formation of HS in nature is one of the least understood aspects of humus chemistry and one of the most intriguing. Historically, there have been three main theories to explain it: the lignin theory of Waksman (1932), the polyphenol theory, and the sugar-amine condensation theory of Maillard (1911). Humic substances are formed by the microbial degradation of dead biota matter , such as lignin , cellulose. ligno-cellulose and charcoal . Humic substances in

3245-409: The source material determine the chemical structure of humic substances. In general, humic substances derived from soil and peat (which takes hundreds to thousands of years to form) have higher molecular weight, higher amounts of O and N, more carbohydrate units, and fewer polyaromatic units than humic substances derived from coal and leonardite (which takes millions of years to form). Isolation id HS

3304-743: The term humate refers to geological materials, such as weathered coal beds (leonardite), mudrock , or pore material in sandstones , that are rich in humic acids. Humate has been mined from the Fruitland Formation of New Mexico for use as a soil amendment since the 1970s, with nearly 60,000 metric tons produced by 2016. Humate deposits may also play an important role in the genesis of uranium ore bodies. The heavy-metal binding abilities of humic acids have been exploited to develop remediation technologies for removing lead from waste water. To this end, Yurishcheva et al. coated magnetic nanoparticles with humic acids. After capturing lead ions,

3363-417: The theory that a 'humification' process created distinct 'humic substances' like 'humic acid', 'fulvic acid', and 'humin'. However, modern chemical analysis methods applied to unprocessed mineral soil have not directly observed large humic molecules. This suggests that the extraction and fractionation techniques used to isolate humic substances alter the original chemical composition of the organic matter. Since

3422-589: The vitalism debate. However, the IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid as organic compounds. Other compounds lacking C-H bonds but traditionally considered organic include benzenehexol , mesoxalic acid , and carbon tetrachloride . Mellitic acid , which contains no C-H bonds, is considered a possible organic compound in Martian soil. Terrestrially, it, and its anhydride, mellitic anhydride , are associated with

3481-445: Was known to occur only in the urine of living organisms. Wöhler's experiments were followed by many others, in which increasingly complex "organic" substances were produced from "inorganic" ones without the involvement of any living organism, thus disproving vitalism. Although vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds. The modern meaning of organic compound

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