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Helen Megaw
Megaw circa 1950
Born	(1907-06-01)1 June 1907 Dublin
Died	26 February 2002(2002-02-26) (aged 94) Ballycastle, County Antrim
Nationality	Irish
Alma mater	Queen's University, Belfast, Girton College, Cambridge
Known for	Crystallographer who determined the structure of ice crystals and the Perovskite crystal structure.
Father	Robert Megaw
Awards	The Roebling Medal of the Mineralogical Society of America. Megaw Island and the mineral Megawite (CaSnO3) are named after her.
Scientific career
Fields	Crystallography
Doctoral advisor	J. D. Bernal
Doctoral students	Robert E. Newnham Sivaramakrishna Chandrasekhar

Helen Dick Megaw (1 June 1907 – 26 February 2002) was an Irish crystallographer who was a pioneer in X-ray crystallography. She made measurements of the cell dimensions of ice and established the Perovskite crystal structure.

Education and career

Megaw was born in Dublin to mathematics teacher Annie McElderry (1874-1968) and judge Robert Megaw, two graduates of Queen's University Belfast who were both originally from Ballymoney, Antrim. She was educated at first at Alexandra College in Dublin, and then briefly at Methodist College in Belfast after the family (including younger brother John, later a leading judge) moved back there in 1921, and finally at the Roedean School in England. While still at school, Megaw read Bragg's X-rays and Crystal Structure. She spent a year at Queen's University, Belfast before moving to Girton College, Cambridge to study Natural Sciences in 1926. She graduated in 1930 and was a research student in crystallography under J. D. Bernal. Megaw's first speciality was the structure of ice, and she was awarded her PhD in 1934, and Girton awarded her a Hertha Ayrton research scholarship which she used to study in Vienna in 1934-1935 under Hermann Francis Mark. In 1935 Megaw co-published with Bernal an influential method for fixing the position of hydrogen atoms known as the Bernal-Megaw model. She spent the year 1935–1936 in Oxford with Francis Simon and then spent several years as a schoolteacher before becoming an industrial crystallographer with Philips Lamps in London in 1943. It was through work at Philips on barium titanate that Megaw first worked on the perovskite crystal structure, on which she established herself as an acknowledged expert. In 1945 Megaw returned to working with Bernal, now at Birkbeck College in London, for a year before taking a post at the Cavendish Laboratory in Cambridge. She became a Fellow and Director of Studies at Girton. Megaw retired in 1972 and divided her time between Cambridge and Ballycastle, County Antrim, where she died in 2002.

Her first book, Ferroelectricity in Crystals, was published in 1957. It was followed by a second book, Crystal Structures: a Working Approach, in 1973.

Following a conversation with Mark Hartland Thomas in 1949 (chief industrial officer of the Council of Industrial Design), Megaw was appointed scientific consultant for the Festival Pattern Group of the Festival of Britain, 1951. She became the prime scientific mover in the group which put crystallographic images in the hands of industrial designers for them to use in products which were displayed at the Festival and in some cases beyond. In 2019, some of Megaw's fabric samples were displayed at the Science Museum, London as part of an exhibition "The Art of Innovation" which explored the relationship between art and science.

Legacy and honors

In recognition of her work in determining the structures of ice crystals, Megaw Island in the Southern Ocean is named for her. Megawite (CaSnO₃), a perovskite-group mineral, is also named after her.

In 1976, Megaw gave a collection of fabric samples from the Festival of Britain along with a souvenir guide-book to the Science Museum in London.

In 1989, Megaw became the first woman to receive the Roebling Medal of the Mineralogical Society of America. She had honorary doctorates from the Universities of Cambridge and Queen's University Belfast.

Bibliography

• Megaw, Helen D (1957). Ferroelectricity in crystals. London: Methuen. OCLC 2226235.
• Megaw, Helen D. (1965). Crystallographic Book List. Boston, MA. ISBN 978-1-4613-4620-3. OCLC 913812505.{{cite book}}: CS1 maint: location missing publisher (link)
• Megaw, Helen D. (1973). Crystal structures: a working approach. Philadelphia: Saunders. ISBN 0-7216-6260-9. OCLC 707007.
• Historical atlas of crystallography. J. Lima-de-Faria, Martin J. Buerger, Jenny P. Glusker, Helen D. Megaw, Paul B. Moore, Marjorie Senechal, William A. Wooster. Dordrecht: Published for International Union of Crystallography by Kluwer Academic Publishers. 1990. ISBN 0-7923-0649-X. OCLC 20933210.{{cite book}}: CS1 maint: others (link)

References

1. A. M. Glazer, "Megaw, Helen Dick (1907–2002)", Oxford Dictionary of National Biography doi:10.1093/ref:odnb/76773
2. ^ "Helen Dick Megaw (1907 - 2002): Mineralogist". The Dictionary of Ulster Biography. Retrieved 20 October 2012.
3. Glazer, Mike (2021). "Helen D. Megaw (1907–2002) and Her Contributions to Ferroelectrics". IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control. 68 (2): 334–338. doi:10.1109/TUFFC.2020.3035268. ISSN 0885-3010.
4. Helen Megaw by Mike Glazer, American Crystallographic Association, 2018
5. ^ Personal papers of Helen Megaw
6. Lesley., Jackson (2008). From atoms to patterns : crystal structure designs from the 1951 Festival of Britain : the story of the Festival Pattern Group. Wellcome Collection. Shepton Beauchamp: Richard Dennis. ISBN 978-0955374111. OCLC 226282421.
7. Lomas, Elizabeth (2001). Guide to the Archive of Art and Design, Victoria & Albert Museum. Taylor & Francis. ISBN 9781579583156.
8. Blatchford, Ian; Blyth, Tilly (2019). The Art of Innovation. Transworld. pp. 216–225. ISBN 9781787632493.
9. "Helen Megaw at the Contributions of 20th Century Women to Physics site". Archived from the original on 6 October 2016.
10. Galuskin, E. V.; Galuskina, I. O.; Gazeev, V. M.; Dzierżanowski, P.; Prusik, K.; Pertsev, N. N.; Zadov, A. E.; Bailau, R.; Gurbanov, A. G. (October 2011). "Megawite, CaSnO3: a new perovskite-group mineral from skarns of the Upper Chegem caldera, Kabardino-Balkaria, Northern Caucasus, Russia". Mineralogical Magazine. 75 (5): 2563–2572. Bibcode:2011MinM...75.2563G. doi:10.1180/minmag.2011.075.5.2563. S2CID 130003129.

External links

• Megaw's collection of samples of fabrics inspired by crystallography from Festival of Britain; now at the Science Museum, London
• "The Souvenir Book of Crystal Designs" from the Festival of Britain

v t e Crystallography
Key concepts	Timeline of crystallography Crystallographers Metallurgy Biocrystallography Structure Unit cell Bravais lattice Miller index Point group Reciprocal lattice Restriction theorem Periodic table Structure prediction Systems Cubic Hexagonal Monoclinic Orthorhombic Tetragonal Triclinic Growth Crystallite Equiaxed Twinning Fiveling Aperiodic crystal Quasicrystal Phase transition Phase diagram Eutectic Miscibility gap Polymorphism Liquid crystal Phase transformation crystallography Precipitation Segregation Spinodal decomposition Supersaturation GP-zone Ostwald ripening Defects Grain boundary Disclination CSL Growth Abnormal growth Perfect crystal Stacking fault Dislocation Burgers vector Partial dislocation Kink Cross slip Frank–Read source Cottrell atmosphere Peierls stress GND Lomer–Cottrell junction Slip Slip bands Interstitials Bjerrum defect Frenkel defect Wigner effect Vacancy Schottky defect F-center Stone–Wales defect Defects in diamond Bragg's law Bragg plane Ewald's sphere Friedel's law Hermann–Mauguin notation Structure factor Thermal ellipsoid
Characterisation	Electron Diffraction Scattering Neutron Diffraction Scattering Nuclear magnetic resonance X-ray Diffraction Scattering
Algorithms	Direct methods Isomorphous replacement Molecular replacement Molecular dynamics Patterson map Phase retrieval Gerchberg–Saxton Single particle analysis
Software	CCP4 Coot CrystalExplorer DSR JANA2020 MTEX OctaDist Olex2 SHELX
Databases	Bilbao Crystallographic Server CCDC CIF COD ICSD ICDD PDB
Journals	Crystal Growth & Design Crystallography Reviews Journal of Chemical Crystallography Journal of Crystal Growth Kristallografija Zeitschrift für Kristallographie – Crystalline Materials Zeitschrift für Kristallographie – New Crystal Structures
Awards	Carl Hermann Medal Ewald Prize Gregori Aminoff Prize
Organisation	IUCr IOBCr RAS DMG Associations Europe France Germany UK US Japan
Category Commons

• 1907 births
• 2002 deaths
• 20th-century Irish women scientists
• 21st-century Irish women scientists
• Irish women chemists
• Crystallographers
• Alumni of Girton College, Cambridge
• Fellows of Girton College, Cambridge
• Scientists from Dublin (city)
• British crystallographers
• Alumni of Queen's University Belfast
• Academics of the University of Cambridge
• People educated at Alexandra College
• People educated at Methodist College Belfast
• People educated at Roedean School, East Sussex
• 20th-century Irish chemists
• Irish women physicists