Accession No

6241

Brief Description

eight ball-and-stick crystal structure models, by Crystal Structures Ltd., English, 2/2 20th century

Origin

England; Cambridge

Maker

Crystal Structures Ltd.

Class

crystallography; demonstration

Earliest Date

1945

Latest Date

1975

Inscription Date

Material

wood (pine?); metal (steel); paint; plastic (unknown type)

Dimensions

[6241.1] 455 x 450 x 230 (mm) [6241.2] 235 x 235 x 235 (mm) [6241.3] 190 x 150 x 150 (mm) [6241.4] 260 x 250 x 240 (mm) [6241.5] 275 x 275 x 275 (mm) [6241.6] 310 x 310 x 310 (mm) [6241.7] 415 x 265 x 275 (mm) [6241.8] 260 x 260 x 230 (mm)

Special Collection

Provenance

Purchased from Dominic Winter Book Auctions, Mallard House, Broadway Lane, South Cerney, Gloucestershire, GL7 5UQ, on or before 6/11/2008. Lot 463.

Inscription

[On plastic tags attached to all 8 models]
CRYSTAL STRUCTURES LTD
339, CHERRY HINTON ROAD,
CAMBRIDGE, ENGLAND.

Description Notes

Eight ball-and-stick crystal structure models, by Crystal Structures Ltd., Cambridge, 2/2 20th century.

Each model is composed of a number of wooden balls (all approximately 20mm to 25mm in diameter), each representing a single atom within the crystal structure model, and painted in a range of colours chosen to distinguish the different elements that make up the crystal structure. The wooden balls are connected by rigid steel rods, with each rod representing a single ‘bond’ between adjacent atoms, with the spacial distribution of the atoms within the crystal structure defined by the angle and length of these rods.

Each model has a plastic tag attached to it, which has embossed on one side the words: “CRYSTAL STRUCTURED LTD, 339, CHERRY HINTON ROAD, CAMBRIDGE, ENGLAND.” On the other side of each tag is written in manuscript the name and composition of the molecule being represented by the model, and the model’s scale:

6241.1 - Tungsten Bronze, K0.6WO3 , 2.5cm = 1Å [red = oxygen, silver = tungsten and gold = potassium]
6241.2 - Caesium Chloride, CsCl , 2.5cm = 1Å [green = chlorine and gold = caesium]
6241.3 - Graphite, 2.5cm = 1Å [black = carbon]
6241.4 - Silver Phosphate , Ag3PO4 , 2.5cm = 1Å [red = oxygen, gold = silver and purple = phosphorus]
6241.5 - Spinel, Al2MgO4 , 2.5cm = 1Å [red = oxygen, gold = aluminium and silver = magnesium]
6241.6 - Ultramarine, Na8Al6Si6O24S2 , 2.5cm = 1Å [red = oxygen, black = silicon, silver = aluminium, gold = sodium, yellow and yellow with black spots = sulphur (?)]
6241.7 - Cadmium Iodide, CaI2 , 2.5cm = 1Å [black = iodine and gold = Cadmium]
6241.8 - Ice (Wurtzite type), H2O , 2.5cm = 1Å [red = oxygen and white = hydrogen]

References

Events

Description
There are several main types of atomic models in use today. Two of the most common are 'ball and spoke' and 'space-filling' types. Each model type displays different information about molecules. Whilst ball and spoke models are designed to show how the atoms bond together, space-filling models accurately demonstrate the size and shape of the molecule. This model kit uses the ‘ball and spoke’ type of modelling to represent the structure of: Tungsten Bronze (6241.1); Caesium Chloride (6241.2); Graphite (6242.3); Silver Phosphate (6242.4), Spinel (6242.5); Ultramarine (6242.6); Cadmium Iodide (6242.7) and Ice [Wurtzite type] (6242.8). Models are essential to teaching and research in chemistry. They are useful tools for visualising the structures and shapes of groups of atoms, which is important in understanding molecular behaviour. The chemist Wilhelm August Hofmann (1818–1892) first used coloured balls to represent the elements around 1865. John Dalton (1766–1844), who significantly shaped nineteenth-century concepts of atom structure, used ball and spoke models in his lectures. This model set was produced by Crystal Structures Ltd., a Cambridge based firm founded in 1947 that specialises in crystal models and bespoke instruments for examining crystal structure.

Display labels:
6241.2:This model shows the atomic structure of caesium chloride, a salt used in the production of electrically-conductive glass, and employed in radiotherapy.

6241.3:This model shows the atomic structure of graphite, one of the common forms of carbon. Graphite is the chief component in pencil lead. The model shows how carbon atoms are arranged into an interlocking crystal lattice of hexagons, with strong horizontal bonds but weaker vertical bonds. This is why graphite is hard yet brittle. When used in pencil lead, layers of the lattice are scraped away from the main crystal, leaving a black trail of carbon on the paper.

6241.4:This colourful model shows the atomic structure of silver phosphate, a poisonous yellow powder used in photographic emulsions and pharmaceuticals. The company that manufactured this model, Crystal Structures Ltd, is still operating in Cambridge.
10/03/2014
Created by: Allison Ksiazkiewicz on 10/03/2014

FM:46715