chemistry

Hydromelonic acid

Hydromelonic acid is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Hydromelonic acid rather than just read about it. In short: Hydromelonic acid, is an elusive chemical compound with formula C9H3N13 or (HNCN)3(C6N7), whose molecule would consist of a heptazine H3(C6N7) molecule, with three cyanamido groups H–N=C=N– or N≡C–NH– substituted for the hydrogen atoms. The compound had not been properly isolated as of 2010, due to its tendency to polymerize.

Key takeaways

Hydromelonic acid belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Hydromelonic acid to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Hydromelonic acid from memory before moving on to harder problems.

Reference excerpt

Hydromelonic acid, is an elusive chemical compound with formula C9H3N13 or (HNCN)3(C6N7), whose molecule would consist of a heptazine H3(C6N7) molecule, with three cyanamido groups H–N=C=N– or N≡C–NH– substituted for the hydrogen atoms. The compound had not been properly isolated as of 2010, due to its tendency to polymerize. However, removal of three protons yields the melonate (formerly hydromelonate) anion (NCN)3(C6N7)3−, whose salts are stable and have been known since the 19th century. Removal of only two protons yields the divalent hydrogenmelonate anion H(NCN)3(C6N7)2−.

History In 1834 Justus von Liebig described the compounds that he named melamine, melam, and melon. In 1835 Leopold Gmelin prepared a potassium salt (later identified as K3[(NCN)3(C6N7)]) by heating potassium ferrocyanide with sulfur); recognizing their connection to the compounds described by Liebig, he named the salt "hydromelonate" and the corresponding acid "hydromelonic". In the following years Liebig prepared the same salt by other methods, such as by fusing potassium thiocyanate with antimony trichloride, and eventually determined the formula C9N13H3 for the acid. The correct structure for the cation was published in 1937 by Linus Pauling and J. H. Sturdivant. Starting in the 1970s, melonates have attracted new interest, motivated by research in cubic carbon nitride c-C3N4. Salts of many cations have been synthesized and studied, including mixed-cation salts and calcium hydrogenmelonate Ca[HC9N13]·7H2O. The structure of potassium melonate pentahydrate K3C9N13·5H2O was elucidated only in 2005.

Preparation Sodium and potassium melonates are still routinely prepared by variations of one of Liebig's methods, namely by reacting melon with molten potassium thiocyanate, potassium cyanate, or sodium thiocyanate. Other salts can be prepared by double displacement reactions.

Melonates

Alkali melonates are soluble in water without decomposition. Treatment of melonates with alkali gives salts of cyameluric acid. Potassium melonate pentahydrate has planar sheets of melonate anions with potassium cations between the layers. The same generals structure is seen in the anhydrous salt (except that the melonate ions are asymmetric due to an NHN– group being turned by 180°) and in the salts Rb3C9N13·3H2O and Cs3C9N13·3H2O. Melonate salts decompose when melted with cyanates to form tricyanomelaminates, the first selective decomposition reaction leading from heptazines to triazines. Pyrolysis of iron(III) melonate Fe[C9N13] at very high temperature yields carbon in the form of nanotubes.

See also Melem, (H2N)3(C6N7) Cyameluric acid, (HO)3(C6N7)

References

Illustrations

Worked examples

Example 1 — a first encounter with Hydromelonic acid

Start with the simplest possible case. Write down what Hydromelonic acid claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Hydromelonic acid before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Hydromelonic acid ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Hydromelonic acid

In research: Hydromelonic acid appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Hydromelonic acid in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Hydromelonic acid is common in secondary-school and first-year university syllabi. It links to neighbouring topics Heterocyclic compounds with 3 rings, Nitriles, Nitrogen heterocycles, so understanding it makes those chapters shorter.
In everyday life: Look for Hydromelonic acid outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Hydromelonic acid in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hydromelonic acid means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Hydromelonic acid out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Hydromelonic acid in simple terms?

Why does Hydromelonic acid matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Hydromelonic acid?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Hydromelonic acid.