Silver behenate is a

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quanti ...

of the long-chain

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, ...

behenic acid. It is a possible low-angle

diffraction standard In crystallography, a diffraction standard, or calibration crystal, is a crystal used to calibrate an X-ray spectrometer to an absolute X-ray energy scale. A range of materials may be used including quartz or silicon crystals. There are also repor ...

that was characterized using the

powder diffraction Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is cal ...

technique.

Description

With the

National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into Outline of p ...

's standard reference material

silicon Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic ...

as an internal standard, the long spacing of silver behenate was accurately determined from the profile-fitted

synchrotron diffraction A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The magnetic field which bends the particle beam into its closed ...

peaks, with d₀₀₁ = 58.380 (3) Å (5.8380(3) nm). This result was in agreement with that obtained from the CuKα pattern. The profile widths of the silver behenate peaks were found to be consistently larger than those of the silicon peaks, indicating significant line broadening for silver behenate. The average

crystallite A crystallite is a small or even microscopic crystal which forms, for example, during the cooling of many materials. Crystallites are also referred to as grains. Bacillite is a type of crystallite. It is rodlike with parallel longulites. Stru ...

size along the long-spacing direction of silver behenate was estimated using the

Scherrer equation The Scherrer equation, in X-ray diffraction and crystallography, is a formula that relates the size of sub-micrometre crystallites in a solid to the broadening of a peak in a diffraction pattern. It is often referred to, incorrectly, as a formula ...

, giving ''D''(avg) = 900 (50) Å (85–95 nm). Diffraction patterns obtained with 1.54 Å synchrotron and CuKα radiation showed thirteen reflections in the 2''θ'' range from 1.5° to 20.0°, which suggests that the compound is suitable for use as an angle-calibration standard for low-angle diffraction. However, care must be taken if silver behenate is to be used as a peak-profile calibration standard because of line broadening.

References

* {{silver compounds Silver compounds Salts of carboxylic acids