Minerals formula writing

Berzelius went further in his attempt to simplify the science. He joined the symbols of the elements to represent the simplest parts of compounds. Thus copper oxide was written CuO, and zinc sulfide ZnS. He had, at first, denoted the number of oxygen atoms by dots and the number of sulfur atoms by commas thus carbon dioxide was C and carbon disulfide was C. But he soon discarded these dots and commas, although for decades after, mineralogists utilized this method of writing the formulas of minerals. 

Qrthoclase feldspar has the chemical formula KAlSi308. What other cations could replace those in this chemical formula Write the resulting formula for two such minerals. 

Thomson used formulae for minerals based on Bergman s, in which A=alumina, S=silica, L=lime, etc. Thomson used quantitative formulae in his paper on oxalates . s =oxygen, c=carbon, A=hydrogen oxalic acid =4k +3C + 2A, sugar = 5 +3c+ 4/1, and used the initial letters of the names as symbols for atomic weights of the elements or acids and bases, also writing chemical formulae. Berzelius used the initial letter or letters of the Latinised names (at first Po, later K, for potassium, kalium). At first the figures were put... 

For a number of reasons, using saturation indices as measures of the mineral masses to be formed as a fluid approaches equilibrium is a futile (if commonly undertaken) exercise. First, a mineral s saturation index depends on the choice of its formula unit. If we were to write the formula for quartz as Si2C>4 instead of Si02, we would double its saturation index. Large formula units have been chosen for many of the clay and zeolite minerals listed in the llnl database, and this explains why these minerals appear frequently at the top of the supersaturation list. 

Give the name and chemical formula for each mineral, and write a balanced equation for the preparation of each element. 

Write a general formula for an anhydrous sodium aluminosilicate which is a framework mineral, containing only tetrahedrally coordinated alu minum and silicon. 

Name some common minerals that contain iron. Write the chemical formula for the iron compound in each. What is the oxidation number of iron in each substance ... 

Boundaries on the diagram are defined by equilibrium conditions between the above phases. Accordingly we write the various reactions between these phases and their equilibrium constant expressions. For simplicity, mineral names are used instead of chemical formulas. The equilibrium constant values which are from Hess (1966), do not differ much from such values in recent use by others (cf. Drever 1988). These values are based in large part on the observed natural behavior of the minerals (cf. Feth et al. 1964 Garrels and Christ 1965 Helgeson 1969). 

The magnitude of the SI is often of little importance. Bethke (1996) and Wolery (1992) point out that the SI value depends not only on the concentrations involved, but on the formula of the mineral. For example, if we were to write the formula of quartz as Si2C>4 instead of Si02, its Saturation Index would be doubled. The choice of large formula units for clays and zeolites explains why these minerals often occur at the top of the supersaturation list (Bethke, 1996, p. 91). 

Write chemical formulas for the following minerals (a) calcite, (b) dolomite, (c) fluorite, (d) halite, (e) corundum, (f) magnetite, (g) beryl, (h) galena, (i) epsomite, (j) anhydrite. 

Write the half-unit-cell formula for a montmorillonite mineral with a layer charge of 0.3, with 90° of the substitution in the octahedral layer (Mg2+ for Al3+) and 10% of the substitution in the tetrahedral layer (Al3+ for Si44-). The saturating cation is Na h. Draw a diagram of this mineral, indicating the position of Mg2+, AI3+, Si4+, and Na+... 

Dubach and Mehta (1963) define humic substances as a series of predominantly aromatic-phenolic polymers, whose acidity is mainly due to carboxyl groups, and which are free of carbohydrates and probably of nitrogen. They state that the presence of quinonic structures cannot be confirmed or excluded. They are of the opinion that there are ether linkages between the aromatic monomers, but humic substances are too nonhomogeneous to justify an attempt to write a structural formula for them, as was done in the past. The humic substances constitute over 50% of the organic matter of mineral soils. At the present time few workers would have any doubt that these substances contain nitrogen. 

The mineral spinel is MgAl204. Spinels have the general formula AB2O4 although later we will also write it as AO B203, where n describes the nonequimolarity. Bragg and Nishikawa actually solved the spinel structure independently in 1915. The spinel structure is so important because the magnetic ferrites are spinels. For the ferrites we express the chemical formula as MO FciOs, where M is a divalent metal ion like Mn, Ni, Fe, or Co (or a mixture of such ions). 

Analyze A mineral is described that has a sheet silicate stmcture with Mg " and OH ions to balance charge and 1.5 Mg for each 1 Si. We are asked to write the empirical formula for the mineral... 

What is the basic unit in cyclic silicate Write its structure. Give the name and formula of a mineral having this structure. 

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