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Oxide and Hydroxide Minerals

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Introduction to Oxides and Hydroxides

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Mineral phases whose structures only produce oxide or hydroxide anions. Oxide and hydroxide minerals make up a small percentage of the Earth's crust by volume. Their geochemical and petrologic significance, on the other hand, cannot be overstated. Metal ores such as iron, aluminium, titanium, uranium, and manganese depend heavily on oxy and hydroxide minerals. Oxide and hydroxide minerals can be found in any geological environment. Some form as primary minerals in igneous rocks, while others form as secondary phases as silicate and sulphide minerals weather and alter. Some minerals, such as oxides and hydroxides, are biogenic. For example, iron(III) and manganese(IV) hydroxides and oxides often result from bacterial oxidation of dissolved Fe2+ and Mn2+in low-temperature aqueous solutions.

Here we will learn about different mineral chemical compound oxides and hydroxides and iron oxides and hydroxides.


Mineral Chemical Compound Oxides and Hydroxides

Positively charged ions of metals or transition elements bind to negatively charged oxygen in oxide minerals, which are inorganic compounds,O2-. Oxide minerals are differentiated from other oxygen-bearing minerals such as silicates, sulphates, borates, phosphates, and carbonates by their classification into simple and complex oxides. Minerals with a hydroxyl group are known as hydroxyl minerals (OH-1) instead of O2- , and oxyhydroxides, which comprise both hydroxyl group and oxygen, are often included in the group of oxide minerals.

The world we live in is based on the technological advancements made possible by oxides and their hydroxide counterparts.

On a molecular level, arrangements of closely knit oxygen atoms with metal or semimetal atoms woven in the spaces between can be found in the oxide family of minerals. Simple oxides are those that have only one form of metal or semimetal attached to them, and complex oxides are those that have several metals incorporated into their molecular structure. The hydroxides, on the other hand, are made up of metals attached to a highly reactive hydroxide ion (OH). Hydroxide minerals are lighter and less compact than oxide minerals since they form at lower temperatures.

While the crowned heads of royal dignitaries are adorned with rubies and sapphires (both colour varieties of the corundum mineral species), spinel, and chrysoberyl, minerals such as chromite (the most important ore of chromium), ilmenite (titanium oxide), and hematite (iron oxide) have provided us with some of the greatest innovations ever made. Iron oxides have played an important role in the cultural, technological, and industrial growth of ancient and modern civilizations, from cave paintings to satellites.

The world we live in is based on the technological advancements made possible by oxides and their hydroxide counterparts. They're also abundant, making up the second most common component of the Earth's crust.


Iron Oxides and Hydroxides

Simple oxides and multiple oxides are the two primary forms of oxides. Simple oxides are made up of a single metal and oxygen in one of many metal combinations: oxygen proportions (X:O): XO,X2O, X2O3, etc. Ice, H2O, is a simple oxide of the X2O type that incorporates hydrogen like the cation. We know that SiO2(quartz and its polymorphs) is the most commonly occurring oxide.

Oxides are found in small quantities in igneous and metamorphic rocks, as well as in sedimentary rocks as preexisting grains. The main ores of iron (hematite and magnetite), chromium (chromite), manganese (pyrolusite, as well as the hydroxides magnitude and romanechite), tin, and uranium all have significant economic value.

The spinel-group minerals have type XY2O4 and contain oxygen atoms in approximate cubic closest packing. Cubic packing of MgAl2O4 is shown below.


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We would find structures of closely knit oxygen atoms with metal or semimetal atoms woven in the spaces between if we could peer into the oxide family of minerals on a molecular scale. Simple oxides are those that have only one form of metal or semimetal attached to them, and complex oxides are those that have several metals incorporated into their molecular structure. The hydroxides, on the other hand, are made up of metals attached to a highly reactive hydroxide ion (OH). Hydroxide minerals are lighter and less compact than oxide minerals since they form at lower temperatures.

While the crowned heads of royal dignitaries are adorned with rubies and sapphires (both colour varieties of the corundum mineral species), spinel, and chrysoberyl, also minerals such as chromite ilmenite (titanium oxide), and hematite (iron oxide) have provided us with some of the greatest innovations ever made. Iron oxides, in particular, have played an important role in the cultural, technological, and industrial growth of ancient and modern civilizations, from cave paintings to satellites.

The most common and most significant sources of iron known to us is hematite (Fe₂O₃). It's a basic oxide with two iron cations and three oxygen anions in its structure. Hematite is a mineral that occurs under a variety of geologic conditions and can be found in a wide range of rock types. Other minerals, such as magnetite (another basic iron oxide) and quartz, may often mix with it.

Another significant hematite deposit is represented by banded iron formations. About two billion years ago, when cyanobacteria in Earth's early oceans started to produce oxygen, a reaction occurred between their oxygen byproduct and iron in the oceans. The ocean floor was left with layers of dark magnetite and crimson, hematite-stained chert, a constant reminder of a planet only starting to exhale.

Hematite is used in a wide range of shapes and sizes. It has a flaky or massive structure, a metallic or earthy lustre, and a dark grey to silver or reddish-brown hue. It may take the shape of a kidney stone, which is a botryoidal form. Roses are flower-like clusters formed by flat hematite crystals. Hematite is distinguished by a distinct reddish-brown streak that occurs when the mineral is struck across a ceramic plate, regardless of its type.

Hematite gets its name from the Greek word for blood, and its dark red powder can be used to stain anything from bricks to make-up when crushed. Prehistoric pigments created from this crushed iron oxide—also known as red ochre in the art world—adorn the walls of sites like France's Chauvet Cave. The use of red ochre evolved along with art and culture. Painters and other artists have been using tubes of the pigment to demonstrate their ideas for decades.

Despite the fact that humans have been mining hematite and other iron oxides for millennia, modern applications have only emerged in the last few decades. Many household products, such as mattress springs, vacuum cleaners, and dishwashers, are made with iron oxides. The manufacture of steel (an alloy of iron and carbon) is perhaps the most significant use of iron oxides today; approximately 98 percent of the iron ore mined in the United States is used in steel production.


Chemical Properties of Oxides

A chemical compound with at least one oxygen atom and one other element in its chemical formula is known as an oxide. An anion of oxygen in the oxidation state of 2 is commonly found in metal oxides. The majority of the Earth's crust is made up of solid oxides, which are formed when elements are oxidised by oxygen in air or water. Carbon monoxide (CO) and carbon dioxide (CO2) are the two main carbon oxides produced by hydrocarbon combustion (CO2). Also materials that are thought to be pure elements may produce an oxide layer. Aluminum foil, for example, produces a thin layer of Al2O3 (known as a passivation layer) that protects it from further corrosion.

Diagram of oxide is shown below


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FAQ (Frequently Asked Questions)

1. Is Iron Soluble or Insoluble in Water?

Ans: Elementary iron dissolves in water under normal conditions. Many iron compounds share this characteristic. Insoluble in water are iron oxide, iron hydroxide, iron carbide, and iron pentacarbonyl.

2. What Happens When Iron Oxidizes?

Ans: Rusting is a form of oxidation. The iron reacts with water and oxygen to form hydrated iron(III) oxide, as a result of this rust will form. As iron and steel come into contact with water and oxygen (both of which are needed for rusting to occur), they rust.

3. Define Hydroxide Ion.

Ans: The hydroxide ion is a negatively charged molecule made up of one oxygen and one hydrogen bound together. The hydroxide ion is a very strong base when dissolved in water.