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Mounting Techniques


Various techniques are uses to mount samples that are sensitive to air, oxygen, mosture, solventloss or are only stable in a particular temperature range. Below we list seveal commonly used techniques.


Specialized
Goniometer Head
The shown goniometer head developed at IUMSC by J. Huffman can be attached to a fitting that allows transfering mounted crystals to the goniometer under N2.

Goniometer head Goniometer head being attached to a fittinge Goniometer head attached to a fitting


Copper Coil The copper coil allows selecting crystals under a stream of cold N2 without mother liquor. The mounted crystal is transferred to the goniometer over a Dewar with liquid N2.

Copper coil in working Copper coil


Dewar Tube Shown is a Dewar tube designed to select under a stream of cold N2 and in mother liquor. The mounted crystal can be transferred to the goniometer while carrying the Dewar with the goniometer head to the diffractometer. This method works well for samples that loose solvent, or are air sensitive. It can also be used for low temperature crystals. The photograph was taken at the University of Leipzig, Germany.

Dewar tube Closeup view of dewar tube


Mark Tube Why Mark tubes: Mark tubes are ideal for air sensitive samples or material that looses solvent. The glass has an absorption coefficient of 97.4(6) (μ/cm-1) for CuKα and 0.5(1.0) (μ/cm-1) for MoKα 10.5(1.0) and a softening point ~500 ºC. The capillaries can be sealed with glues, waxes or via melting. Temperature-sensitive samples can be sealed on a Schlenk line while under vacuum or in protetctive atmosphere (Ar, N2) as shown below. Temperature-sensitive compounds can be sealed in a capillary by connecting it to a Schlenk vessel and sealing it over a Dewar with part of the Mark capillary immersed in a cold environment, e.g. cold mixtures or liquid nitrogen.

capillary mark tube sealing



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