Special report

A crystallographer's road trip "down under"

Christopher Sumby

Australian and New Zealand researchers have an enduring association with the technique of X-ray crystallography, with Adelaide in Australia being the birthplace of Sir William Lawrence Bragg and the technique being widely developed through the pioneering contributions of Arthur Lindo Patterson and Maurice Wilkins, who were both born in New Zealand [1]. Crystallography in the two countries has blossomed through the joint Society of Crystallographers in Australia and New Zealand (SCANZ) [2] and with crystallographers active in most major universities, medical research institutes and government-funded research organisations. These researchers are all supported by landmark infrastructure run by the Australian Nuclear Science and Technology Organisation (ANSTO), namely the Australian Centre for Neutron Scattering near Sydney and the Australian Synchrotron in Melbourne.

Figure 1. The Mitchell Building, the site of Sir William Henry Bragg's laboratory at the University of Adelaide, South Australia (photo credit: Chris Sumby).

With travel restrictions starting to relax worldwide, and particularly in Australia ahead of Melbourne's hosting the 26th Congress and General Assembly of the International Union of Crystallography (IUCr 2023), it seems an ideal time to think about some opportunities for travel. Australia and New Zealand, as members of the society hosting the IUCr 2023 congress, have a wealth of historical sites related to the discovery and development of X-ray diffraction, natural beauty spots displaying the fundamentals of crystallography, and visitor attractions with links to the technique. This item covers a potential "road trip," taking in some of the possible sites that crystallographers visiting the IUCr Congress in Melbourne in 2023 might want to consider. If you like the ideas here, why don't you check out the IUCr 2023's website (https://iucr2023.org/) and subscribe to their E-zine containing details of the "The Great Down Under Road Trip" for more details?

Whichever way you look at it, travel around Australia and New Zealand represents a big trip – it's around a five-hour flight from the west coast to the east coast in Australia and another three-hour flight from the eastern seaboard of Australia to New Zealand. There are lots to see, but some planning is required given the large distances involved – driving east to west or north to south in Australia is one of those "once in a lifetime" experiences given the unpopulated nature of most of the country and the distances.

As the birthplace of W. L. Bragg, Adelaide is a treasure trove of sights to interest the crystallographer. His father, W. H. Bragg, was the first Professor of Physics and Mathematics at the University of Adelaide, and his lab in the Mitchell Building of the University [3], on the main boulevard at the top of the city is still there, albeit reincarnated as the legal counsel's office (Fig. 1). The University has a vast array of documents and items from the Bragg era, and these are commonly on display. In the "new" Physics Building, busts of both Braggs are on display (Fig. 2).

Figure 2. Busts of W. L. and W. H. Bragg in the Physics Building of the University of Adelaide (photo credit: Helen Maynard-Casely).

These are copies of busts on display on North Terrance, just outside the South Australian governor general's residence. The South Australian Museum, which is also on North Terrace, has a fine collection of minerals from around Australia (Fig. 3) and a display of the Ediacaran fossils, the earliest known complex multicellular organisms [4]. Adelaide is also home to the Royal Institution of Australia (RI-Aus) [5], the sister institution to the UK's Royal Institution, and around the outskirts of the city centre, in North Adelaide and by the East Parklands, are the residences that the Bragg family called home while living in Australia.

Figure 3. Some of the mineral collection at the South Australian Museum (photo credit: Chris Sumby).

Mining the abundant natural resources of Australia is an important industry, and there are some interesting sites. About eight hours drive north of Adelaide is the town of Coober Pedy, the so-called Opal capital of Australia [6]. In this outback town, temperatures in summer can be extreme, and a number of residents live underground in caves and dugouts. Coober Pedy was once covered by an ocean that allowed silica minerals to accumulate in rock cracks and cavities and led to the formation of opals. Unlike most gemstones, though, opals are non-crystalline, but the experience of outback Australia is still an interesting one.

Heading west from Adelaide and South Australia takes one over 1500 km across the expansive Nullabor plain to Western Australia (a two to three day drive depending on where you choose to start and end) [7]. Perth is one of the most isolated cities in the world but has been a strength of Australian X-ray crystallography for many years, under the auspices of Ted Maslen, Allan White and many others [1]. A homage to quasicrystals can be found in the Bayliss Building of the University of Western Australia (UWA), where the floor is covered in a beautiful Penrose tile floor [8]. Perth was the host city when Australia first hosted the Congress and General Assembly of the International Union of Crystallography in 1987.

A trip to Australia would not be complete without a visit to the "top-end" and the spectacular national parks Kakadu [9], Litchfield [10] and Uluṟu-Kata Tjuṯa National Park [11], the last home to the sandstone monolith known as Uluru. Kakadu and Litchfield National Parks can be accessed from Darwin, while Alice Springs is the gateway to the Red Centre desert, with spectacular scenery and walks. Near Alice Springs are spectacular salt lakes, such as the 180km-long Lake Amadeus, which is twice as salty as the sea and is estimated to contain 600 million tons of salt crystals [12]. These lakes, which are typically only accessible on guided tours, glow pink in the early morning light and silver in the moonlight. Alice Springs also claims a connection to the Braggs – being named after Alice Todd, who was W. H. Bragg's mother-in-law and W. L. Bragg's grandmother.

Sticking with the theme of minerals and gemstones, the Queensland outback towns of Emerald, Sapphire and Rubyvale are found in the central highlands, inland from Rockhampton, and about 10 hours drive northwest of the state capital Brisbane [13]. There are lots of opportunities to fossick for gems and tour mine heritage sites.

Heading south from here takes you to Parkes, five hours west of Sydney, where the "The Dish" – The Parkes Radio telescope – is located. You can read all about this in the first IUCr 2023 newsletter E-Zine. Heading east to the coast again brings you to Sydney, one of the common arrival points for visitors. South of the city is Lucas Heights, home to ANSTO's OPAL reactor [14] and a suite of neutron diffraction instruments in the Australian Centre for Neutron Scattering [15]. Science Discovery Tours provide a tour of the world of nuclear science and the work ANSTO does in the areas of health, the environment and delivering solutions for industry.

There are plenty of options from here. One can push onto Victoria and the site of IUCr 2023. Alternatively, one can fly over Victoria to the southernmost state of Tasmania or head across the "ditch" to New Zealand. Tasmania, the "apple isle," is an area of significant natural beauty and home to several crystallographic sites. The tessellated pavement, just one hour's drive from the state capital, Hobart, is a picturesque natural wonder consisting of tile-like rocks along the water's edge [16]. A spectacular cubic rock, "cube rock" can be found in northeast Tasmania for those who appreciate crystals. On the slopes of South Mt Cameron, the rock is surrounded by beautiful views, including Little Blue Lake, the site of an abandoned tin mine, and views of Cameron Regional Park [17].

If you are coming "down under" for IUCr 2023, then a trip "across the ditch" before or after the conference is a must. Flights to New Zealand are available from most mainland Australian capital cities, and the South Island of New Zealand is a must-see. Down the west coast of the South Island is Punakaiki, also known as the Pancake Rocks, an area where the wild West Coast seas form blowholes amongst layers of rock [18]. These "pancakes" formed below the ocean floor as softer sandstone and harder limestone layers before the sandwiched rock was lifted out of the ocean by earthquake activity. Erosion by wind and rain led to these spectacular stacks, like the crystallographic planes of a layered crystal. Heading further south along the West Coast past, with spectacular glaciers and forest, leads one to Lake Matheson, where spectacular reflection symmetry mirrors New Zealand – Aotearoa's – tallest mountain, Aoraki (Mt Cook) in the water [19].

From Lake Matheson, near Fox Glacier, one can travel over the Haast Pass to Queenstown and then north through the Mackenzie Country or out to the east coast. If you take this route, a stop at Moeraki Boulders, a beach dotted with hundreds of nearly spherical stones half-buried in the sand is recommended [20]. The crystallographic connection is to spherically ground 2-dimethylsufuranylidene-1,3-indanedione (YLID) crystals, which are used as test crystals for diffractometer alignment and instrument testing [21].

Victoria is the final state on our crystallographer's road trip and the state capital, Melbourne, our destination. About four hours drive northwest of Melbourne is Lake Tyrrell, a 120,000-year-old shallow salt lake known for its spectacular views [22]. The drive also takes you up into the Mallee, a region named after the form of certain species of eucalyptus trees, which grow with multiple stems springing from an underground lignotuber. Alternatively, if you want something a little closer to Melbourne, then 90 minutes east of the city is Warburton and Cement Creek Redwood Forest, where 1500 Californian Redwood trees form a perfect periodic array [23]. On the way back, stop in Clayton to see the Australian Synchrotron, where "first light" was achieved in June 2006. Today, as part of the Bright project [24], seven new beamlines will be constructed to complement the existing nine. The new beamlines include MX3 for macromolecular and chemical crystallography, BioSAXS and Advanced Diffraction and Scattering Beamlines. Come 2023, several of these will be in operation.

The Australian and New Zealand crystallographic community is very excited to host IUCr 2023 and to welcome international researchers "down under" for this event. Hopefully, you can enjoy some or all of this crystallographic road trip "down under" in the lead up to or following the congress, and this article has provided some inspiration.

Thanks to Dr Helen Maynard-Casely for the inspiration for the article and to the Twitter crystallographic hive mind for their suggestions of local sights worth visiting. To get further ideas and more information, visit IUCr 2023's website (https://iucr2023.org/) and subscribe to their E-zine containing details of the "The Great Down Under Road Trip."