Information: - A fumarole (or "fumerole" - the word ultimately comes from the Latin "fumus", "smoke") is an opening in a planet's crust, often in areas surrounding volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, and hydrogen sulfide. The steam forms when superheated water vaporizes as its pressure drops when it emerges from the ground. The name solfatara, from the Italian "solfo", "sulfur" (via the Sicilian language - compare to the volcano Solfatara), is given to fumaroles that emit sulfurous gases. - Sulfur or sulphur (see spelling and etymology) is a chemical element with symbolS and atomic number16. It is abundant, multivalent, and nonmetalic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S. Elemental sulfur is a bright yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, and the noble gases. - The mica group of sheet silicate (phyllosilicate) minerals includes several closely related materials having nearly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition. The nearly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms. - India, officially the Republic of India ("Bhrat Gaarjya"), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country (with over 1.2 billion people), and the most populous democracy in the world. It is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west; China, Nepal, and Bhutan to the northeast; and Myanmar (Burma) and Bangladesh to the east. In the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. India's Andaman and Nicobar Islands share a maritime border with Thailand and Indonesia. Its capital is New Delhi; other metropolises include Mumbai, Kolkata, Chennai, Bangalore, Hyderabad and Ahmedabad. - Sal ammoniac is a rare mineral composed of ammonium chloride, NHCl. It forms colorless, white, or yellow-brown crystals in the isometric-hexoctahedral class. It has very poor cleavage and a brittle to conchoidal fracture. It is quite soft, with a Mohs hardness of 1.5 to 2, and it has a low specific gravity of 1.5. It is water-soluble. Sal ammoniac is also the archaic name for the chemical compound ammonium chloride. The Romans called the ammonium chloride deposits that they collected from near the Temple of Jupiter Amun (Greek "Ammon") in ancient Libya 'sal ammoniacus' (salt of Amun) because of proximity to the nearby temple. Salts of ammonia have been known from very early times; the term "Hammoniacus sal" appears in the writings of Pliny, but it is not known whether the term is identical with the more modern "sal-ammoniac". In any case, that salt ultimately gave ammonia and ammonium compounds their name. - Anthracite is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest calorific content of all types of coal except for graphite. - Ammonia or azane is a compound of nitrogen and hydrogen with the formula NH. The simplest pnictogen hydride, ammonia is a colourless gas with a characteristic pungent smell. It contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. - Bararite is a natural form of ammonium fluorosilicate (also known as hexafluorosilicate or fluosilicate). It has chemical formula (NH)SiF and trigonal crystal structure. This mineral was once classified as part of cryptohalite. Bararite is named after the place where it was first described, Barari, India. It is found at the fumaroles of volcanoes (Vesuvius, Italy), over burning coal seams (Barari, India), and in burning piles of anthracite (Pennsylvania, U.S.). It is a sublimation product that forms with cryptohalite, sal ammoniac, and native sulfur. - Italy, officially the Italian Republic, is a unitary parliamentary republic in Europe. Located in the heart of the Mediterranean Sea, Italy shares open land borders with France, Switzerland, Austria, Slovenia, San Marino and Vatican City. Italy covers an area of and has a largely temperate seasonal climate and Mediterranean climate; due to its shape, it is often referred to in Italy as "lo Stivale" (the Boot). With 61 million inhabitants, it is the fourth most populous EU member state. - Pennsylvania (Pennsylvania German: "Pennsylvaani"), officially the Commonwealth of Pennsylvania, is a state located in the northeastern and Mid-Atlantic regions of the United States. The Appalachian Mountains run through its middle. The commonwealth borders Delaware to the southeast, Maryland to the south, West Virginia to the southwest, Ohio to the west, Lake Erie and the Canadian province of Ontario to the northwest, New York to the north, and New Jersey to the east. - Halite (or ), commonly known as rock salt, is a type of salt, the mineral form of sodium chloride (NaCl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount and type of impurities. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates. - Ammonium fluorosilicate ( also known as ammonium hexafluorosilicate , ammonium fluosilicate or ammonium silicofluoride ) has the formula ( NH4 ) 2SiF6 . It is a toxic chemical , like all salts of fluorosilicic acid . It is made of white crystals , which have at least three polymorphs and appears in nature as rare minerals cryptohalite or bararite . - A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. After reading the paragraphs above, we are interested in knowing the entity with which 'ammonium fluorosilicate' exhibits the relationship of 'instance of'. Find the answer from the choices below. Choices: - acid - area - bay - border - chemical - chemical compound - chemical element - chloride - city - class - country - democracy - food - formula - group - halite - hydrogen - india - italy - lake - language - may - mineral - number - object - opening - part - province - republic - rock - room - salt - sea - share - state - temperature - three - variety - volcano - water - word
chemical compound